View Filing Data

Print Document View Excel Document

Document and Entity Information	12 Months Ended
Document and Entity Information	Dec. 31, 2016 shares
Entity Registrant Name	GDS Holdings Ltd
Entity Central Index Key	0001526125
Document Type	20-F
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Class A
Entity Common Stock, Shares Outstanding	692,418,707
Class B
Entity Common Stock, Shares Outstanding	67,590,336

Consolidated Balance Sheets - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets
Cash (including cash of VIEs of RMB12,032 and RMB397,948 as of December 31, 2015 and 2016, respectively)	¥ 1,811,319	¥ 924,498
Restricted cash (including restricted cash of VIEs of RMB nil and RMB10,091 as of December 31, 2015 and 2016, respectively)	27,673	6,425
Accounts receivable, net of allowance for doubtful accounts (including accounts receivables, net of allowance for doubtful accounts of VIEs of RMB3,847 and RMB172,538 as of December 31, 2015 and 2016, respectively)	198,851	111,013
Value-added-tax ("VAT") recoverable (including VAT recoverable of VIEs of RMB1,389 and RMB13,399 as of December 31, 2015 and 2016, respectively)	72,958	59,680
Prepaid expenses (including prepaid expenses of VIEs of RMB5,173 and RMB28,466 as of December 31, 2015 and 2016, respectively)	50,361	51,395
Other current assets (including other current asset of VIEs of RMB234 and RMB1,201 as of December 31, 2015 and 2016, respectively)	49,151	33,688
Total current assets	2,210,313	1,186,699
Property and equipment, net (including property and equipment, net of VIEs of RMB5,830 and RMB1,421,036 as of December 31, 2015 and 2016, respectively)	4,322,891	2,512,687
Intangible assets, net (including intangible assets, net of VIEs of RMB nil and RMB54,558 as of December 31, 2015 and 2016, respectively)	92,569	46,935
Prepaid land use rights, net	26,792	27,408
Goodwill	1,341,087	1,294,664	¥ 1,294,664
Deferred tax assets (including deferred tax assets of VIEs of RMB nil and RMB8,178 as of December 31, 2015 and 2016, respectively)	12,626	2,363
VAT recoverable (including VAT recoverable of VIEs of nil and RMB12,094 as of December 31, 2015 and 2016, respectively)	98,863	0
Other non-current assets (including other non-current assets of VIEs of RMB nil and RMB36,357 as of December 31, 2015 and 2016, respectively)	98,725	57,516
Total assets	8,203,866	5,128,272
Current liabilities
Short-term borrowings and current portion of long-term borrowings (including short-term borrowings and current portion of long-term borrowings of VIEs of RMB nil and RMB413,600 as of December 31, 2015 and 2016, respectively)	628,478	428,218
Accounts payable (including accounts payable of VIEs of RMB 4,151 and RMB 152,192 as of December 31, 2015 and 2016, respectively)	513,543	215,658
Accrued expenses and other payables (including accrued expenses and other payables of VIEs of RMB 1,802 and RMB125,989 as of December 31, 2015 and 2016 respectively)	207,950	118,316
Due to a related party		67,604
Deferred revenue (including deferred revenue of VIEs of RMB 8,992 and RMB30,033 as of December 31, 2015 and 2016, respectively)	40,657	46,508
Capital lease and other financing obligations, current (including capital lease and other financing obligations, current of VIEs of RMB nil and RMB55,311 as of December 31, 2015 and 2016, respectively)	88,593	48,745
Total current liabilities	1,479,221	925,049
Long-term borrowings, excluding current portion	1,509,676	958,264
Convertible bonds payable	1,040,550	648,515
Capital lease and other financing obligations, non-current (including capital lease and other financing obligations, non-current of VIEs of RMB nil and RMB631,874 as of December 31, 2015 and 2016, respectively)	1,022,959	424,939
Deferred tax liabilities (including deferred tax liabilities of VIEs of RMB nil and RMB39,426 as of December 31, 2015 and 2016, respectively)	53,280	37,691
Other long-term liabilities (including other long-term liabilities of VIEs of RMB nil and RMB8,717 as of December 31, 2015 and 2016, respectively)	111,706	79,005
Total liabilities	5,217,392	3,073,463
Redeemable preferred shares (US$0.00005 par value; 350,563,436 shares authorized; 349,087,677 shares issued and outstanding with aggregate redemption amount of RMB2,277,059 as of December 31, 2015)		2,395,314
Shareholders' Equity (deficit)
Ordinary shares (US$0.00005 par value; 675,636,564 and 2,002,000,000 shares authorized; 217,987,922 and 760,009,043 shares issued and outstanding as of December 31, 2015 and 2016, respectively)	260	76
Additional paid-in capital	4,036,959	303,621
Accumulated other comprehensive loss	(192,080)	(61,949)
Accumulated deficit	(858,665)	(582,253)
Total shareholders' equity (deficit)	2,986,474	(340,505)	¥ (16,565)	¥ (301,199)
Total liabilities, redeemable preferred shares and shareholders' equity (deficit)	¥ 8,203,866	¥ 5,128,272

Consolidated Balance Sheets (Parenthetical) ¥ in Thousands	Dec. 31, 2016 CNY (¥) shares	Dec. 31, 2015 CNY (¥) shares
Current assets, VIEs
Cash	¥ 1,811,319	¥ 924,498
Restricted cash	27,673	6,425
Accounts receivable, net of allowance for doubtful accounts	198,851	111,013
Value-added-tax ("VAT") recoverable	72,958	59,680
Prepaid expenses	50,361	51,395
Other current assets	49,151	33,688
Property and equipment, net	4,322,891	2,512,687
Intangible assets, net	92,569	46,935
Noncurrent deferred tax assets	12,626	2,363
VAT recoverable, non-current	98,863	0
Other non-current assets	98,725	57,516
Current liabilities, VIEs
Short-term borrowings and current portion of long-term borrowings	628,478	428,218
Accounts payable	513,543	215,658
Accrued expenses and other payables	207,950	118,316
Deferred revenue	40,657	46,508
Capital lease and other financing obligations, current	88,593	48,745
Long-term borrowings, excluding current portion	1,509,676	958,264
Capital lease and other financing obligations, non-current	1,022,959	424,939
Deferred tax liabilities	53,280	37,691
Other long-term liabilities	¥ 111,706	¥ 79,005
Redeemable preferred shares, authorized \| shares		350,563,436
Redeemable preferred shares, issued \| shares		349,087,677
Redeemable preferred shares, outstanding \| shares		349,087,677
Redeemable preferred shares, aggregate redemption amount		¥ 2,277,059
Ordinary shares, shares authorized \| shares	2,002,000,000	675,636,564
Ordinary shares, shares issued \| shares	760,009,043	217,987,922
Ordinary shares, shares outstanding \| shares	760,009,043	217,987,922
VIEs
Current assets, VIEs
Cash	¥ 397,948	¥ 12,032
Restricted cash	10,091	0
Accounts receivable, net of allowance for doubtful accounts	172,538	3,847
Value-added-tax ("VAT") recoverable	13,399	1,389
Prepaid expenses	28,466	5,173
Other current assets	1,201	234
Property and equipment, net	1,421,036	5,830
Intangible assets, net	54,558	0
Noncurrent deferred tax assets	8,178	0
VAT recoverable, non-current	12,094	0
Other non-current assets	36,357	0
Current liabilities, VIEs
Short-term borrowings and current portion of long-term borrowings	413,600	0
Accounts payable	152,192	4,151
Accrued expenses and other payables	125,989	1,802
Deferred revenue	30,033	8,992
Capital lease and other financing obligations, current	55,311	0
Long-term borrowings, excluding current portion	0	0
Capital lease and other financing obligations, non-current	631,874	0
Deferred tax liabilities	39,426	0
Other long-term liabilities	¥ 8,717	¥ 0

Consolidated Statements of Operations - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidated Statements of Operations
Net revenue	¥ 1,055,960	¥ 703,636	¥ 468,337
Cost of revenue	(790,286)	(514,997)	(388,171)
Gross profit	265,674	188,639	80,166
Operating expenses
Selling and marketing expenses	(71,578)	(57,588)	(40,556)
General and administrative expenses	(227,370)	(128,714)	(113,711)
Research and development expenses	(9,100)	(3,554)	(1,597)
Loss from operations	(42,374)	(1,217)	(75,698)
Other income (expenses):
Interest income	2,070	1,355	6,935
Interest expenses	(265,234)	(126,901)	(131,908)
Foreign currency exchange (loss) gain, net	18,310	11,107	(875)
Government grants	2,217	3,915	4,870
Gain on remeasurement of equity investment			62,506
Others, net	284	1,174	(412)
Loss before income taxes	(284,727)	(110,567)	(134,582)
Income tax benefits	8,315	11,983	4,583
Net loss	(276,412)	(98,584)	(129,999)
Extinguishment of redeemable preferred shares			(106,515)
Change in redemption value of redeemable preferred shares	205,670	(110,926)	(69,116)
(Cumulative) Dividend on preferred shares	(332,660)	(7,127)	(3,509)
Net loss attributable to ordinary shareholders	¥ (403,402)	¥ (216,637)	¥ (309,139)
Loss per ordinary share
Basic and diluted (in CNY per share)	¥ (1.35)	¥ (0.99)	¥ (1.91)
Weighted average number of ordinary share outstanding
Basic and diluted (in share)	299,093,937	217,987,922	162,070,745

Consolidated Statements of Comprehensive Loss - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidated Statements of Comprehensive Loss
Net loss	¥ (276,412)	¥ (98,584)	¥ (129,999)
Other comprehensive income (loss)
Foreign currency translation adjustments, net of nil tax	(130,131)	(118,491)	4,114
Comprehensive loss	¥ (406,543)	¥ (217,075)	¥ (125,885)

Consolidated Statements of Comprehensive Loss (Parenthetical) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidated Statements of Comprehensive Loss
Foreign currency translation adjustments, tax	¥ 0	¥ 0	¥ 0

Consolidated Statements of Changes in Shareholders' Deficit - CNY (¥) ¥ in Thousands	Ordinary Shares	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit	Total
Balance at Dec. 31, 2013	¥ 43		¥ 52,428	¥ (353,670)	¥ (301,199)
Balance (in shares) at Dec. 31, 2013	110,000,001
Changes in shareholders deficit
Loss for the year				(129,999)	(129,999)
Other comprehensive income (loss)			4,114		4,114
Comprehensive loss			4,114	(129,999)	(125,885)
Acquisition of EDC Holding Limited and its subsidiaries (''EDC Holding'')	¥ 27	¥ 472,918			472,945
Acquisition of EDC Holding Limited and its subsidiaries (''EDC Holding'') (in shares)	88,352,558
Issuance of shares in exchange for bonds payable	¥ 12	205,524			205,536
Issuance of shares in exchange for bonds payable (in shares)	38,397,655
Repurchase of ordinary shares	¥ (6)	(119,658)			(119,664)
Repurchase of ordinary shares (in shares)	(18,762,292)
Extinguishment of redeemable preferred shares upon repurchase		(76,900)			(76,900)
Extinguishment of redeemable preferred shares upon exchange		(29,615)			(29,615)
Change in redemption value of redeemable preferred shares		(69,116)			(69,116)
Share-based compensation		27,333			27,333
Balance at Dec. 31, 2014	¥ 76	410,486	56,542	(483,669)	(16,565)
Balance (in shares) at Dec. 31, 2014	217,987,922
Changes in shareholders deficit
Loss for the year				(98,584)	(98,584)
Other comprehensive income (loss)			(118,491)		(118,491)
Comprehensive loss			(118,491)	(98,584)	(217,075)
Change in redemption value of redeemable preferred shares		(110,926)			(110,926)
Share-based compensation		4,061			4,061
Balance at Dec. 31, 2015	¥ 76	303,621	(61,949)	(582,253)	¥ (340,505)
Balance (in shares) at Dec. 31, 2015	217,987,922				217,987,922
Changes in shareholders deficit
Loss for the year				(276,412)	¥ (276,412)
Other comprehensive income (loss)			(130,131)		(130,131)
Comprehensive loss			(130,131)	(276,412)	(406,543)
Issuance of ordinary shares - initial public offering	¥ 54	1,221,464			1,221,518
Issuance of ordinary shares - initial public offering (in shares)	160,565,880
Declaration of preference dividend in ordinary shares		(343,296)			(343,296)
Settlement of preference dividend in ordinary shares	¥ 11	266,783			266,794
Settlement of preference dividend in ordinary shares (in shares)	31,490,164
Conversion of redeemable preference share	¥ 118	2,311,014			2,311,132
Conversion of redeemable preference share (in shares)	349,087,677
Change in redemption value of redeemable preferred shares		205,670			205,670
Settlement of liability-classified restricted shares award	¥ 1	7,538			7,539
Settlement of liability-classified restricted shares award (in shares)	877,400
Share-based compensation		64,165			64,165
Balance at Dec. 31, 2016	¥ 260	¥ 4,036,959	¥ (192,080)	¥ (858,665)	¥ 2,986,474
Balance (in shares) at Dec. 31, 2016	760,009,043				760,009,043

Consolidated Statements of Cash Flows ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)	Dec. 31, 2014 CNY (¥)
Cash flows from operating activities:
Net loss	¥ (276,412)	¥ (98,584)	¥ (129,999)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Amortization of debt issuance cost and debt discount	5,917		33,874
Depreciation and amortization	227,355	145,406	82,753
Net gain on disposal of property and equipment	(62)		(37)
Share-based compensation expense	64,165	4,061	27,333
Gain on remeasurement of equity investment			(62,506)
Allowance for doubtful accounts	(2,156)		2,156
Deferred tax benefit	(10,624)	(10,589)	(5,024)
Changes in operating assets and liabilities, net of effect of acquisitions:
Increase of accounts receivable	(79,383)	(37,647)	(11,851)
Increase of VAT recoverable	(94,588)	(41,431)	(16,197)
(Increase) decrease of prepaid expenses	1,034	(15,017)	(3,499)
Increase of restricted cash	(21,248)	(6,425)
Decrease (increase) of other current assets	(20,534)	(12,287)	81,334
Decrease (increase) of other non-current assets	(24,820)	(22,766)	4,105
(Decrease) increase of accounts payable	43,844	(5,150)	(6,760)
(Decrease) increase of due to related parties	(2,668)	2,668	(3,086)
Increase (decrease) of deferred revenue	(5,851)	3,207	10,675
Increase (decrease) of accrued expenses and other payables	22,018	(1,071)	18,293
Increase of other long-term liabilities	23,785	15,327	6,373
Net cash provided by (used in) operating activities	(150,228)	(80,298)	27,937
Cash flows from investing activities:
Payments for purchase of property and equipment	(987,763)	(732,979)	(248,349)
Loans made to a related party			(307,048)
Loans made to WTENG	(42,000)
Cash acquired from the acquisition of subsidiaries	1,237		40,999
Cash paid for the acquisition of subsidiaries	(103,600)		(13,592)
Deposit paid for a potential acquisition	(15,000)
Proceeds from sale of property and equipment	62	52	163
Release of restricted cash related to purchase of property and equipment		1,022	4,078
Net cash used in investing activities	(1,147,064)	(731,905)	(523,749)
Cash flows from financing activities:
Proceeds from short-term borrowings	339,777	333,000	298,307
Proceeds from long-term borrowings	1,269,996	584,457	200,000
Repayment of short-term borrowings	(433,000)	(289,000)	(357,307)
Repayment of long-term borrowings	(373,946)	(137,709)	(115,936)
Payment of issuance cost of borrowings	(57,438)	(24,310)
Proceeds from issuance of convertible bonds	327,580	648,950
Proceeds from issuance of bonds payable			114,950
Repayment of bonds payable		(14,330)	(4,081)
Proceeds from a related party loan		64,936
Repayment of a related party loan	(65,474)
Proceeds from issuance of Series C redeemable preferred shares			1,521,295
Payment of issuance costs of Series C redeemable preferred shares			(20,128)
Net proceeds from issuance of ordinary shares for initial public offering	1,221,518
Payment of preferred shares dividends	(76,502)
Repurchase of ordinary shares			(119,664)
Repurchase of redeemable preferred shares		(23,300)	(455,366)
Payment under capital lease and other financing obligations	(23,897)	(17,934)	(9,057)
Restricted cash released upon repayment of borrowings		2,925	3,274
Net cash provided by financing activities	2,128,614	1,127,685	1,056,287
Effect of exchange rate changes on cash	55,499	2,258	(2,328)
Net increase in cash	886,821	317,740	558,147
Cash at beginning of year	924,498	606,758	48,611
Cash at end of year	1,811,319	924,498	606,758
Supplemental disclosures of cash flow information
Interest paid	228,678	81,216	55,149
Income tax paid	5,645	853	443
Supplemental disclosures of non-cash investing and financing activities
Payables for purchase of property and equipment	128,901	20,402	73,709
Purchase of property and equipment through capital leases and other financing arrangement	568,984	¥ 205,000
Consideration payable for the acquisition of WTENG	25,900
Issuance of ordinary shares to settle preference dividend	¥ 266,794
Issuance of ordinary shares in exchange of bonds payable			205,536
Issuance of ordinary and preferred shares for the acquisition of EDC Holding			¥ 1,184,242

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	12 Months Ended
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	Dec. 31, 2016
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	1 DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (a) Description of business GDS Holdings Limited (the “Parent” or “GDS Holdings”) was incorporated in the Cayman Islands on December 1, 2006. GDS Holdings and its consolidated subsidiaries and consolidated variable interest entities (collectively referred to as “the Company”) are principally engaged in providing colocation, managed hosting and managed cloud services in the People’s Republic of China (the “PRC”). The Company operates its data centers in Hong Kong Special Administrative Region, Shanghai Municipality, Beijing Municipality, Jiangsu Province, Guangdong Province and Sichuan Province of the PRC and serves customers that primarily operate in the internet and banking industries. (b) Basis of presentation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”). The consolidated financial statements are presented in Renminbi (“RMB”), rounded to the nearest thousand. The accompanying consolidated financial statements contemplate the realization of assets and the satisfaction of liabilities in the normal course of business. The realization of assets and the satisfaction of liabilities in the normal course of business are dependent on, among other things, the Company’s ability to operate profitably, to generate cash flows from operations, and to pursue financing arrangements, including obtaining new bank borrowings or renewing its existing bank borrowings. Historically, the Company relied on external bank and third party loans and issuances of preferred shares and convertible bonds to fund its working capital and capital expenditure requirements and to meet its obligations and commitments when they become due. On November 7, 2016, the Company closed its initial public offering in which the Company offered and sold 19,250,000 American depositary shares (“ADSs”) representing 154,000,000 Class A ordinary shares, at a price of US$10.00 per ADS for an offering size of approximately US$192,500. On December 6, 2016, the underwriters exercised their option to purchase from the Company 820,735 additional ADSs representing 6,565,880 Class A ordinary shares for an offering size of approximately US$8,207.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

12 Months Ended

Dec. 31, 2016

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

(a) Principles of Consolidation

The accompanying consolidated financial statements include the financial statements of GDS Holdings Limited, its subsidiaries and consolidated variable interest entities (“VIEs”) for which the Company is the primary beneficiary. The VIEs are Beijing Wanguo Chang’an Science and Technology Co., Ltd., (“GDS Beijing”) and Shanghai Shu’an Data Services Co., Ltd., (“GDS Shanghai”).

In certain regions of the PRC, the Company’s operations are conducted through VIEs to comply with the PRC laws and regulations, which prohibit foreign investments in companies that are engaged in data center related business in those regions. Individuals acting as nominee equity holders hold the legal equity interests of the VIEs on behalf of the Company. The equity holders of the VIEs are the CEO of the Company and his relative.

Prior to the internal restructuring (the “2016 Variable Interest Entity Restructuring”), the Company primarily conducted its operations through Global Data Solutions Co., Ltd. (“GDS Suzhou”), a wholly owned subsidiary. Shanghai Waigaoqiao EDC Technology Co, Ltd., or EDC Shanghai Waigaoqiao also conducted operations. In order to adapt to the new regulatory requirements in China, the Company completed the 2016 Variable Interest Entity Restructuring whereby GDS Suzhou and EDC Shanghai Waigaoqiao were converted into PRC domestic companies that are wholly owned by GDS Beijing on April 13, 2016 and August 9, 2016, respectively. Prior to the internal restructuring, GDS Beijing was a VIE of GDS Suzhou through a series of contractual agreements, including the equity interest pledge agreements, shareholder voting rights proxy agreement, exclusive technology license and service agreements, exclusive call option agreements and loan agreements (collectively, the “VIE Agreements”). The conversion of GDS Suzhou and EDC Shanghai Waigaoqiao into PRC domestic companies were accomplished by way of transferring all of the equity interests in GDS Suzhou and EDC Shanghai Waigaoqiao to GDS Beijing. In connection with the internal restructuring, the VIE Agreements between GDS Beijing and GDS Suzhou were terminated and concurrently, new contractual VIE Agreements were entered into between GDS Beijing and Shanghai Free Trade Zone GDS Management Co., Ltd. (“GDS Management Company”), a newly-established subsidiary of the Company. The terms of the new contractual arrangements between GDS Beijing and GDS Management Company are identical to the terms of the VIE Agreements between GDS Beijing and GDS Suzhou. The Company continues to be the primary beneficiary of the VIEs following the completion of the internal restructuring.

Since the entities involved in the 2016 Variable Interest Entity Restructuring are all under common control and the Company is the primary beneficiary of GDS Beijing at the time of transfer, the net assets of GDS Suzhou and EDC Shanghai Waigaoqiao transferred to GDS Beijing is recorded at the same amounts at which the assets and liabilities would have been measured if they had not been transferred. That is, no gain or loss is recognized because of such transfer.

The following is a summary of the contractual VIE Agreements entered among GDS Management Company, the VIEs, and the shareholders of the VIEs.

Equity Interest Pledge Agreements. Pursuant to the equity interest pledge agreements, each shareholder of the VIEs has pledged all of his or her equity interest in the VIEs as a continuing first priority security interest, as applicable, to respectively guarantee the VIEs and their shareholders’ performance of their obligations under the relevant contractual arrangement, which include the exclusive technology license and service agreement, loan agreement, exclusive call option agreement, shareholder voting rights proxy agreement and, only with respect to GDS Shanghai, an intellectual property rights license agreement. If the VIEs or any of their shareholders breach their contractual obligations under these agreements, GDS Management Company, as pledgee, will be entitled to certain rights regarding the pledged equity interests, including receiving proceeds from the auction or sale of all or part of the pledged equity interests of the VIEs in accordance with PRC law. Each of the shareholders of the VIEs agrees that, during the term of the equity interest pledge agreements, he or she will not dispose of the pledged equity interests or create or allow creation of any encumbrance on the pledged equity interests without the prior written consent of GDS Management Company. The equity interest pledge agreements remain effective until the VIEs and their shareholders discharge all their obligations under the contractual arrangements.

Shareholder Voting Rights Proxy Agreement. Pursuant to the shareholder voting rights proxy agreements, each shareholder of the VIEs has irrevocably appointed the PRC citizen(s) as designated by GDS Management Company to act as such shareholder’s exclusive attorney-in-fact to exercise all shareholder rights, including, but not limited to, voting on all matters of the VIEs requiring shareholder approval, disposing of all or part of the shareholder’s equity interest in the VIEs, and appointing directors and executive officers. GDS Management Company is also entitled to change the appointment by designating another PRC citizen(s) to act as exclusive attorney-in-fact of the shareholders of the VIEs with prior notice to such shareholders. Each shareholder voting rights proxy agreement will remain in force for so long as the shareholder remains a shareholder of the VIE.

Exclusive Technology License and Service Agreements. Under the exclusive technology license and service agreements, GDS Management Company licenses certain technology to the VIEs and GDS Management Company has the exclusive right to provide the VIEs with technical support, consulting services and other services. Without GDS Management Company’s prior written consent, the VIEs agree not to accept the same or any similar services provided by any third party. The VIEs agree to pay service fees on a yearly basis and at an amount equivalent to all of its net profits as confirmed by GDS Management Company. GDS Management Company owns the intellectual property rights arising out of its performance of these agreements. In addition, the VIEs have granted GDS Management Company an exclusive right to purchase or to be licensed with any or all of the intellectual property rights of the VIEs at the lowest price permitted under PRC law. Unless otherwise agreed by the parties, these agreements will continue to remain effective at all times.

Intellectual Property Rights License Agreement. Pursuant to an intellectual property rights license agreement between GDS Management Company and GDS Shanghai, GDS Shanghai has granted GDS Management Company an exclusive license to use for free any or all of the intellectual property rights owned by GDS Shanghai from time to time, and without the parties’ prior written consent, GDS Shanghai cannot take any actions, including without limitation to, transferring or licensing outside its ordinary course of business any intellectual property rights to any third parties, which may affect or undermine GDS Management Company’s use of the licensed intellectual property rights from GDS Shanghai. The parties have also agreed under the agreement that GDS Management Company should own the new intellectual property rights developed by it regardless whether such development is dependent on any of the intellectual property rights owned by GDS Shanghai. This agreement can only be early terminated by prior mutual consent of the parties and need to be renewed upon GDS Management Company’s unilateral request.

Exclusive Call Option Agreements. Pursuant to the exclusive call option agreements, the shareholders of the VIEs have irrevocably granted GDS Management Company an exclusive option to purchase, or have its designated person or persons to purchase, at its discretion, to the extent permitted under PRC law, all or part of such shareholders’ equity interests in the VIEs. The purchase price should equal to the minimum price required by PRC law or such other price as may be agreed by the parties in writing. Without GDS Management Company’s prior written consent, the shareholders of the VIEs have agreed that the VIEs shall not amend the articles of association, increase or decrease the registered capital, sell or otherwise dispose of their assets or beneficial interest, create or allow any encumbrance on their assets or other beneficial interests, provide any loans, or distribute dividends to the shareholders. These agreements will remain effective until all equity interests of the VIEs have been transferred or assigned to GDS Management Company or its designated person(s).

Loan Agreements. Pursuant to the loan agreements between GDS Management and the shareholders of the VIEs, GDS Management agrees to extend loans in an aggregate amount of RMB310,100 to the shareholders of the VIEs solely for their capitalization or equity contribution into the VIEs. Pursuant to the loan agreements, GDS Management Company has the right to require repayment of the loans upon delivery of thirty-day’s prior notice to the shareholders, and the shareholders can repay the loans by either sale of their equity interests in the VIEs to GDS Management Company or its designated person(s) pursuant to their respective exclusive option agreements, or other methods as determined by GDS Management Company pursuant to its articles of association and the applicable PRC laws and regulations.

Under the terms of the VIE Agreements, the Company has (i) the right to receive service fees on a yearly basis at an amount equivalent to all of the net profits of the VIEs under the exclusive technology license and services agreements when such services are provided; (ii) the right to receive all dividends declared by the VIEs and the right to all undistributed earnings of the VIEs; (iii) the right to receive the residual benefits of the VIEs through its exclusive option to acquire 100% of the equity interests in the VIEs, to the extent permitted under PRC law; and (iv) the right to require each of the shareholder of the VIEs to appoint the PRC citizen(s) as designated by GDS Management Company to act as such shareholder’s exclusive attorney-in-fact to exercise all shareholder rights, including, but not limited to, voting on all matters of the VIEs requiring shareholder approval, disposing of all or part of the shareholder’s equity interest in the VIEs, and appointing directors and executive officers.

In accordance with ASC 810-10-25-38A, the Company has a controlling financial interest in the VIEs because the Company has (i) the power to direct activities of the VIEs that most significantly impact the economic performance of the VIEs; and (ii) the obligation to absorb the expected losses and the right to receive expected residual return of the VIEs that could potentially be significant to the VIEs. The terms of the VIE Agreements and the Company’s financial support to the VIEs were considered in determining that the Company is the primary beneficiary of the VIEs. Accordingly, the financial statements of the VIEs are consolidated in the Company’s consolidated financial statements.

Under the terms of the VIE Agreements, the VIEs’ equity holders have no rights to the net assets nor have the obligations to fund the deficit, and such rights and obligations have been vested to the Company. All of the equity (net assets) or deficits (net liabilities) and net income (loss) of the VIEs are attributed to the Company.

The Company has been advised by its PRC legal counsel that each of the VIE agreements is valid, binding and enforceable in accordance with its terms and applicable PRC laws and the ownership structure of the VIEs does not violate applicable PRC Laws. However, there are substantial uncertainties regarding the interpretation and application of PRC laws and future PRC laws and regulations. There can be no assurance that the PRC authorities will take a view that is not contrary to or otherwise different. If the current ownership structure of the Company and the VIE Agreements are determined to be in violation of any existing or future PRC laws and regulations, the PRC government could:

Levy fines on the Company or confiscate income of the Company;

Revoke or suspend the VIEs’ business or operating licenses;

Discontinue or place restrictions or onerous conditions on VIE’s operations;

Require the Company to discontinue their operations in the PRC;

Require the Company to undergo a costly and disruptive restructuring;

Take other regulatory or enforcement actions that could be harmful to the Company’s business.

The imposition of any of these government actions could result in the termination of the VIE agreements, which would result in the Company losing the (i) ability to direct the activities of the VIEs and (ii) rights to receive substantially all the economic benefits and residual returns from the VIEs and thus result in the deconsolidation of the VIEs in the Company’s consolidated financial statements.

The assets and liabilities of the VIEs are presented parenthetically on the face of the consolidated balance sheets. Net revenue, net income, operating, investing and financing cash flows of the VIEs that were included in the Company’s consolidated financial statements for the years ended December 31, 2014, 2015 and 2016 are as follows:

	Years ended December 31,
	2014		2015		2016
Net revenue	9,244		30,598		846,168
Net (loss) income	(4,799	)	(5,327	)	22,246
Net cash (used in) provided by operating activities	(1,034	)	8,631		239,624
Net cash used in investing activities	(20	)	(1,456	)	(158,681	)
Net cash provided by financing activities	—		—		304,973

The unrecognized revenue producing assets that are held by the VIEs comprise of internally developed software, intellectual property and trademarks which were not recorded on the Company’s consolidated balance sheets as they do not meet all the capitalization criteria.

(b) Use of estimates

The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant items subject to such estimates and assumptions include, but are not limited to, the useful lives of long-lived assets, the fair values of assets acquired and liabilities assumed and the consideration transferred in a business combination, the fair value of the reporting unit for the goodwill impairment test, the allowance for doubtful accounts receivable, the realization of deferred income tax assets, the fair value of share-based compensation awards, the recoverability of long-lived assets and the fair value of the asset retirement obligation. Changes in facts and circumstances may result in revised estimates. Actual results could differ from those estimates, and as such, differences may be material to the consolidated financial statements.

The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. The Company does not have any cash equivalents as of December 31, 2015 and 2016.

(d) Restricted cash

Restricted cash represents amounts held by banks, which are not available for the Company’s use, as security for issuance of commercial acceptance notes relating to purchase of property and equipment, letters of guarantee or bank borrowings and the related interest. Upon maturity of the commercial acceptance notes, letters of guarantee and repayment of bank borrowings, the deposits are released by the bank and available for general use by the Company. Restricted cash is reported within cash flows from operating, investing or financing activities in the consolidated statements of cash flows with reference to the purpose of the restriction.

(e) Fair value of financial instruments

The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels (note 16 to the consolidated financial statements):

Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date.

Level 2 Inputs: Other than quoted prices included in Level 1 inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability.

Level 3 Inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date.

(f) Accounts receivable

Accounts receivable are recorded at the invoiced amount and do not bear interest. Amounts collected on trade accounts receivable are included in net cash provided by operating activities in the consolidated statements of cash flows. The Company maintains an allowance for doubtful accounts for estimated losses inherent in its accounts receivable portfolio. In establishing the required allowance, management considers historical losses adjusted to take into account current market conditions and customers’ financial condition, the amount of receivables in dispute, the accounts receivables aging, and the customers’ repayment patterns. The Company reviews its allowance for doubtful accounts on a customer-by-customer basis. Account balances are charged off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. The Company does not have any off-balance-sheet credit exposure related to its customers.

(g) Property and equipment

Property and equipment are carried at cost less accumulated depreciation and any recorded impairment. Property and equipment acquired under capital leases are initially recorded at the present value of minimum lease payments.

Gains or losses arising from the disposal of an item of property and equipment are determined based on the difference between the net disposal proceeds and the carrying amount of the item and are recognized in profit or loss on the date of disposal.

The estimated useful lives are presented below.

Buildings		20 - 30 years
Data center equipment
- Machinery		10 - 20 years
- Other equipment		3 - 5 years
Leasehold improvement		Shorter of the lease term and the
		estimated useful lives of the assets
Furniture and office equipment		3 - 5 years
Vehicles		5 years

Construction in progress primarily consists of the cost of data center buildings and the related construction expenditures that are required to prepare the data center buildings for their intended use.

No depreciation is provided in respect of construction in progress until it is substantially completed and ready for its intended use. Once a data center building is ready for its intended use and becomes operational, construction in progress is allocated to the property and equipment categories and is depreciated over the estimated useful life of the underlying assets.

Depreciation on property and equipment is calculated on the straight-line method over the estimated useful lives of the assets. For assets acquired under a capital lease, the assets are amortized in a manner consistent with the Company’s normal depreciation policy for owned assets if the lease transfers ownership to the Company by the end of the lease term or contains a bargain-purchase-option. Otherwise, assets acquired under a capital lease are amortized over the lease term.

(h) Long-lived assets held for sale

Long-lived assets are classified as held-for-sale if: (1) the Company has committed to a plan to sell the assets that are available for sale in its present condition, including initiating actions to complete the sale that is probable to qualify for as a completed sale within one year; (2) it is unlikely that significant changes to the plan will be made or the plan will be withdrawn; (3) the assets are being marketed for sale at a price that is reasonable in related to its current value. Long-lived assets held for sale are recorded at the lower of carrying value and fair value less cost to sell. A loss shall be recognized for any initial or subsequent write-down to fair-value less cost to sell. Long-lived assets held for sale are not depreciated while classified as held for sale.

In August 2014, the Company entered into an agreement with a customer for the development, construction and sale of an ancillary property and the related land right. As of December 31, 2016, all the conditions precedent to the sale of the property have not been performed, and therefore no revenue or income was recognized during the periods presented. The cost of the property held for sale of RMB9,075 is recorded in other current assets (note 4).

(i) Leases

Leases are classified at the lease inception date as either a capital lease or an operating lease. A lease is a capital lease if any of the following conditions exists: a) ownership is transferred to the lessee by the end of the lease term, b) there is a bargain purchase option, c) the lease term is at least 75% of the property’s estimated remaining economic life, or d) the present value of the minimum lease payments at the beginning of the lease term is 90% or more of the fair value of the leased property to the lessor at the inception date. The Company records a capital lease as an asset and an obligation at an amount equal to the present value at the beginning of the lease term of minimum lease payments during the lease term.

The Company records an asset and related financing obligation for the estimated construction costs under build-to-suit lease arrangements where it is considered the owner for accounting purposes, to the extent the Company is involved in the construction of the building or structural improvements or has construction risk prior to commencement of a lease. Upon completion of the construction and commencement of the lease terms, the Company assesses whether these arrangements qualify for sales recognition under the deemed sale-leaseback transaction. If the arrangements do not qualify for sales recognition under the sale-leaseback accounting guidance, the Company continues to be the deemed owner of the build-to-suit assets for financial reporting purposes. The Company keeps the construction costs of the assets on its balance sheet. In addition, lease payments less the portion considered to be interest expense decrease the financing liability.

As of December 31, 2015 and 2016, assets under capital leases and other financing obligations represent data center buildings and data center equipment.

Rental costs on operating leases are charged to expense on a straight-line basis over the lease term. Certain operating leases contain rent holidays and escalating rent. Rent holidays and escalating rent are considered in determining the straight-line rent expense to be recorded over the lease term. Rental costs associated with building operating leases that are incurred during the construction of leasehold improvements and to otherwise ready the property for the Company’s intended use are recognized as rental expenses and are not capitalized.

(j) Asset retirement costs

The Company’s asset retirement obligations are primarily related to its data center buildings, of which the majority are leased under long-term arrangements, and, in certain cases, are required to be returned to the landlords in their original condition.

The fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred. The corresponding asset retirement costs are capitalized as part of the cost of leasehold improvements and are depreciated over the shorter of the asset or the term of the lease subsequent to the initial measurement. The Company accretes the liability in relation to the asset retirement obligations over time and the accretion expense is recorded in cost of revenue.

Asset retirement obligations are recorded in other long-term liabilities. The following table summarizes the activity of the asset retirement obligation liability:

Asset retirement obligations as of January 1, 2014		—
Additions		2,148
Accretion expense		73


Asset retirement obligations as of December 31, 2014		2,221
Additions		3,299
Accretion expense		255


Asset retirement obligations as of December 31, 2015		5,775
Additions		2,942
Accretion expense		588


Asset retirement obligations as of December 31, 2016		9,305

(k) Intangible assets

Intangible assets acquired in the acquisition comprised of customer relationships and favorable leases.

The weighted-average amortization period by major intangible asset class is as follows:

Customer relationships	5-8 years
Favorable lease	20 years

Customer relationships represent the orders, backlog and customer lists, which arise from contractual rights or through means other than contracts. Customer relationships are amortized using a straight-line method, as the pattern in which the economic benefits of the intangible assets are consumed or used up cannot be reliably determined.

Favorable lease is recognized as an intangible asset if the terms of the acquiree’s operating lease are favorable relative to market terms. Favorable lease is amortized on a straight-line method over the lease term.

(l) Prepaid land use rights

The land use rights represent the amounts paid and relevant costs incurred for the rights to use land in the PRC and are carried at cost less accumulated amortization. Amortization is provided on a straight-line basis over the term of the land use right of 50 years.

(m) Goodwill

Goodwill is an asset representing the future economic benefits arising from other assets acquired in the acquisition that are not individually identified and separately recognized.

Goodwill is not amortized but is tested for impairment annually or more frequently if events or changes in circumstances indicate that it might be impaired. Goodwill is tested for impairment at the reporting unit level on an annual basis and between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying value. These events or circumstances could include a significant change in the stock prices, business climate, legal factors, operating performance indicators, competition, or sale or disposition of a significant portion of a reporting unit. Application of the goodwill impairment test requires judgment, including the identification of the reporting unit, assignment of assets and liabilities to the reporting unit, assignment of goodwill to the reporting unit, and determination of the fair value of each reporting unit.

The Company has the option to perform a qualitative assessment to determine whether it is more-likely-than not that the fair value of a reporting unit is less than its carrying value prior to performing the two-step goodwill impairment test. If it is more-likely-than-not that the fair value of a reporting unit is greater than its carrying amount, the two-step goodwill impairment test is not required. If the two-step goodwill impairment test is required, first, the fair value of the reporting unit is compared with its carrying amount (including goodwill). If the fair value of the reporting unit is less than its carrying amount, an indication of goodwill impairment exists for the reporting unit and the Company performs step two of the impairment test (measurement). Under step two, an impairment loss is recognized for any excess of the carrying amount of the reporting unit’s goodwill over the implied fair value of that goodwill. The implied fair value of goodwill is determined by allocating the fair value of the reporting unit in a manner similar to a purchase price allocation and the residual fair value after this allocation is the implied fair value of the reporting unit goodwill. No impairment losses were recorded for goodwill for the years ended December 31, 2014, 2015 and 2016.

(n) Impairment of long-lived assets

Long-lived assets, such as property and equipment, intangible assets subject to amortization and prepaid land use rights are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset or asset group be tested for possible impairment, the Company first compares undiscounted cash flows expected to be generated by that asset or asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary. No impairment losses were recorded for long-lived assets for the years ended December 31, 2014, 2015 and 2016.

(o) Value-added-tax (“VAT”)

Entities that are VAT general taxpayers are permitted to offset qualified input VAT paid to suppliers against their output VAT upon receipt of appropriate supplier VAT invoices on an entity by entity basis. When the output VAT exceeds the input VAT, the difference is remitted to tax authorities, usually on a monthly basis; whereas when the input VAT exceeds the output VAT, the difference is treated as VAT recoverable which can be carried forward indefinitely to offset future net VAT payables. VAT related to purchases and sales which have not been settled at the balance sheet date is disclosed separately as an asset and liability, respectively, in the consolidated balance sheets.

As of December 31, 2016, the Company recorded a VAT recoverable of RMB72,958 (2015:RMB 59,680) in current assets and RMB98,863 (2015: RMB nil) in non-current assets and VAT payables of RMB5,954 (2015: RMB2,962) in accrued expenses and other payables, in the consolidated balance sheets.

(p) Derivative financial instruments

Derivative financial instruments are recognized initially at fair value. At the end of each reporting period, the fair value is remeasured. The gain or loss on remeasurement to fair value is recognized immediately in profit or loss.

(q) Commitment and contingencies

Liabilities for loss contingencies arising from claims, assessments, litigation, fines, and penalties and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. Legal costs incurred in connection with loss contingencies are expensed as incurred.

(r) Revenue recognition

The Company recognizes revenue when delivery of the service or product has occurred, collection of the relevant receivable is probable, persuasive evidence of an arrangement exists and the sales price is fixed or determinable.

These criteria as they relate to each of the following major revenue generating activities are described below.

The Company derives revenue primarily from the delivery of (i) colocation services; (ii) managed hosting services and; (iii) managed cloud services. The remainder of the Company’s revenue is from IT equipment sales that are either sold on a stand-alone basis or bundled in a managed hosting service contract arrangement and consulting services.

Colocation services are services where the Company provides space, power and cooling to customers for housing and operating their IT system equipment in the Company’s data centers. Colocation services are provided to customers for a fixed amount over the contract service period, ranging from 1 to 6 years. Revenues from colocation services are recognized on a straight line basis over the term of the contract. The Company has determined that its performance pattern to be straight line since the customer receives value as the services are rendered continuously during the term of the contract, the earning process is straight-line, and there is no other discernible performance pattern of recognition.

Managed hosting services are services where the Company provides outsourced services to manage the customers’ data center operations, including data migration, IT operations, security and data storage. Managed hosting services are primarily provided to financial institution customers as a business continuity and disaster recovery solution. Managed hosting services are provided to customers for a fixed amount over the contract service period ranging from 1 to 6 years. Revenues from managed hosting services are recognized on a straight line basis over the term of the contract. The Company has determined that its performance pattern to be straight line since the customer receives value as the services are rendered continuously during the term of the contract, the earning process is straight-line, and there is no other discernible performance pattern of recognition.

In certain colocation and managed hosting service contracts, the Company agrees with the customers that the Company will charge the customers for the actual power consumption. The Company records the chargeable power consumption as service revenue in the consolidated statements of operations.

Revenue recognized for colocation or managed hosting and cloud services delivered prior to billing is recorded within accounts receivable. The Company generally bills the customer in equal instalments on a monthly or quarterly basis.

Cash received in advance from customers prior to the delivery of the colocation or managed hosting and cloud services is recorded as deferred revenue.

Managed cloud services are services where the Company delivers virtual storage and computing services to customers. Managed cloud services are provided to customers for a fixed amount over the subscription period, ranging from 1 to 3 years. Revenues from managed cloud services are recognized ratably over the subscription period once all requirements for recognition have been met, including provisioning the service so that it is available to the customers.

The sale of IT equipment is recognized when delivery has occurred and the customer accepts the equipment and the Company has no performance obligation after the delivery.

In certain managed hosting service contracts, the Company sells and delivers IT equipment such as servers and computer terminals prior to the delivery of the services. Since the delivered item has value to the customer on a standalone basis and there is no general right of return for the equipment, the equipment is considered a separate unit of accounting. Accordingly, the contract consideration is allocated to the equipment and the managed hosting services based on their relative standalone selling prices. The consideration allocated to the delivered equipment is not contingent on the delivery of the services or meeting other specified performance conditions. That is, payment on the equipment is due upon the delivery of the equipment and is not contingent upon the delivery of the undelivered services.

Consulting services are provided to customers for a fixed amount over the service period, usually less than one year. The Company’s consulting contracts do not specify any interim milestones, (other than for payment based on passage of time), or deliverables. The Company recognizes revenues from consulting services using the proportional performance method based on the pattern of service provided to the customers.

Sales taxes collected from customers and remitted to governmental authorities are excluded from revenues in the consolidated statements of operations.

(s) Cost of revenues

Cost of revenues consists primarily of utility costs, depreciation of property and equipment, rental costs, labor costs and other costs directly attributable to the provision of the service revenue.

(t) Research and development and advertising costs

Research and development and advertising costs are expensed as incurred. Research and development costs amounted to RMB1,597, RMB3,554 and RMB9,100 in 2014, 2015 and 2016, respectively. Research and development costs consist primarily of payroll and related personnel costs for developing or significantly improving the Company’s services and products.

Advertising costs amounted to RMB2,363, RMB4,128 and RMB8,942 in 2014, 2015 and 2016, respectively.

(u) Start-up costs

Pre-operating or start-up costs incurred prior to operating a new data center are expensed as incurred and consist primarily of rental costs of operating leases of buildings during the construction of leasehold improvements and other miscellaneous costs incurred prior to the operation of the data centers. Start-up costs amounted to RMB16,217, RMB25,659 and RMB12,976 were recorded in general and administrative expenses in in 2014, 2015 and 2016, respectively.

(v) Government grants

Government grants are recognized when received and when all the conditions for their receipt have been met. Subsidies that compensate the Company for expenses incurred are recognized as a reduction of expenses in the consolidated statements of operations. Subsidies that are not associated with expenses are recognized as other income.

Subsidies for the acquisition of property and equipment are recorded as a liability until earned and then depreciated over the useful life of the related assets as a reduction of the depreciation charges. Subsidies for obtaining the rights to use land are recorded as a liability until earned and then amortized over the land use right period as a reduction of the amortization charges of the related land use rights. In 2010 and 2011, the Company received government subsidies that required the Company to operate in a particular area for a certain period. The Company recorded the subsidies in other long-term liabilities when the subsidies were received and subsequently recognized as government subsidy income ratably over the period the Company is required to operate in the area.

As of December 31, 2015 and 2016, deferred government grants of RMB16,268 and RMB14,051 are recorded in other long-term liabilities in the consolidated balance sheets.

(w) Capitalized interest

A reconciliation of total interest costs to ‘‘Interest expenses’’ as reported in the consolidated statements of operations for 2014, 2015 and 2016 is as follows:

	Years ended December 31,
	2014		2015		2016

Total interest costs	136,458		138,260		324,085
Less: interest costs capitalized	(4,550	)	(11,359	)	(58,851	)

Interest expenses	131,908		126,901		265,234

Interest costs that are directly attributable to the construction of an asset which necessarily takes a substantial period of time to get ready for its intended use or sale are capitalized as part of the cost of that asset. The capitalization of interest costs as part of the cost of a qualifying asset commences when expenditure for the asset is being incurred, interest costs are being incurred and activities that are necessary to prepare the asset for its intended use or sale are in progress. Capitalization of interest costs is ceased when the asset is substantially complete and ready for its intended use.

(x) Debt issuance costs

Debt issuance costs are capitalized and are amortized over the life of the related loans based on the effective interest method. Such amortization is included as a component of interest expense.

The Company early adopted Accounting Standards Update 2015-03, Interest—Imputation of Interest (‘‘ASU 2015-03’’), during the year ended December 31, 2015. In accordance with ASU 2015-03, debt issuance costs of RMB23,908 and RMB74,246 are presented as a reduction of debt as of December 31, 2015 and 2016, respectively.

(y) Income tax

Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest related to unrecognized tax benefits in interest expense and penalties in general and administrative expenses.

In the fourth quarter of 2016, the Company early adopted Accounting Standards Update (“ASU”) No. 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes, and prior periods were not retrospectively adjusted (note 2(ee)).

(z) Share-based compensation

The Company accounts for the compensation cost from share-based payment transactions with employees based on the grant-date fair value of the equity instrument issued. The grant-date fair value of the award is recognized as compensation expense, net of estimated forfeitures, over the period during which an employee is required to provide service in exchange for the award, which is generally the vesting period. When no future services are required to be performed by the employee in exchange for an award of equity instruments, and if such award does not contain a performance or market condition, the cost of the award is expensed on the grant date. The Company recognizes compensation cost for an award with only service conditions that has a graded vesting schedule on a straight-line basis over the requisite service period for the entire award, provided that the cumulative amount of compensation cost recognized at any date at least equals the portion of the grant-date value of such award that is vested at that date.

Awards granted to employees with performance conditions attached are measured at fair value on the grant date and are recognized as the compensation expenses in the period and thereafter when the performance goal becomes probable to achieve. Awards granted to employees with market conditions attached are measured at fair value on the grant date and are recognized as the compensation expenses over the estimated requisite service period, regardless of whether the market condition has been satisfied if the requisite service period is fulfilled.

The Company recognizes the estimated compensation cost of service-based restricted share based on the fair value of its ordinary shares on the date of the grant. The Company recognizes the compensation cost, net of estimated forfeitures, over its respective vesting term. The Company recognizes the estimated compensation cost of performance-based restricted share based on the fair value of its ordinary shares on the date of the grant. The rewards are earned upon attainment of identified performance goals. The Company recognizes the compensation cost, net of forfeitures, over the performance period. The Company also adjusts the compensation cost based on the probability of performance goal achievement at the end of each reporting period.

Forfeitures are estimated at the time of grant and revised in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting option and restricted share units forfeitures and record stock-based compensation expense only for those awards that are expected to vest.

Share-based payment transactions with nonemployees in which goods or services are received in exchange for equity instruments are accounted for based on the fair value of the consideration received or the fair value of the equity instrument issued, whichever is more reliably measurable. The measurement date of the fair value of the equity instrument issued is the earlier of either the date on which the counterparty’s performance is complete or the date at which a commitment for performance by the counterparty to earn the equity instrument is reached.

For further information on stock-based compensation, see Note 18 below.

(aa) Employee benefits

Pursuant to relevant PRC regulations, the Company is required to make contributions to various defined contribution plans organized by municipal and provincial PRC governments. The contributions are made for each PRC employee at rates ranging from 28% to 49% on a standard salary base as determined by local social security bureau. Contributions to the defined contribution plans are charged to the consolidated statements of operations when the related service is provided.

(bb) Foreign currency translation and foreign currency risks

The functional currency of GDS Holdings is the USD, whereas the functional currency of its PRC subsidiaries and consolidated VIEs is the RMB.

Foreign currency transactions during the period are translated at the foreign exchange rates ruling at the transaction dates. Monetary assets and liabilities denominated in foreign currencies are translated at the foreign exchange rates ruling at the end of the reporting period. Exchange gains and losses are recognized in profit or loss and are reported in foreign currency exchange (loss) gain on a net basis.

The results of foreign operations are translated into RMB at the exchange rates approximating the foreign exchange rates ruling at the dates of the transactions. Assets and liabilities are translated at the exchange rates at the balance sheet date, equity accounts are translated at historical exchange rates and revenues, expenses, gains and losses are translated using the average rate for the year.

Translation adjustments are reported in other comprehensive income and accumulated in the translation adjustment component of equity until the sale or liquidation of the foreign entity.

The RMB is not a freely convertible currency. The PRC State Administration for Foreign Exchange, under the authority of the PRC government, controls the conversion of RMB to foreign currencies. The value of the RMB is subject to changes of central government policies and international economic and political developments affecting supply and demand in the China foreign exchange trading system market. The Company’s cash and restricted cash denominated in RMB amounted to RMB200,004 and RMB501,125 as of December 31, 2015 and 2016, respectively. As of December 31, 2016, the Company’s cash and restricted cash were deposited in major financial institutions located in PRC, Hong Kong, and Cayman Island financial institutions, and were denominated in the following currencies:

	RMB	USD	HKD	JPY	EUR
In PRC	491,631	32,783	—	—	—
In Hong Kong	9,494	153,307	12,546	6,592	96
In Cayman Island	—	4,993	—	—	—

Total in original currency	501,125	191,083	12,546	6,592	96

RMB equivalent	501,125	1,325,547	11,222	394	704

(cc) Concentration of credit risk

Financial instruments that potentially expose the Company to concentrations of credit risk consist principally of cash and cash equivalent, restricted cash, and accounts receivable. The Company’s investment policy requires cash and cash equivalents and restricted cash to be placed with high-quality financial institutions and to limit the amount of credit risk from any one issuer. The Company regularly evaluates the credit standing of the counterparties or financial institutions.

The Company conducts credit evaluations on its customers prior to delivery of goods or services. The assessment of customer creditworthiness is primarily based on historical collection records, research of publicly available information and customer on-site visits by senior management. Based on this analysis, the Company determines what credit terms, if any, to offer to each customer individually. If the assessment indicates a likelihood of collection risk, the Company will not deliver the services or sell the products to the customer or require the customer to pay cash, post letters of credit to secure payment or to make significant down payments. Historically, credit losses on accounts receivable have been insignificant.

(dd) Earnings (loss) per share

Basic earnings (loss) per ordinary share is computed by dividing net income (loss) attributable to the Company’s ordinary shareholders by the weighted average number of ordinary shares outstanding during the year using the two-class method. Under the two-class method, net income (loss) attributable to the Company’s ordinary shareholders is allocated between ordinary shares and other participating securities based on participating rights in undistributed earnings. The Company’s preferred shares (note 15) are participating securities since the holders of these securities participate in dividends on the same basis as ordinary shareholders. These participating securities are not included in the computation of basic loss per ordinary share in periods when the Company reports net loss, because these participating security holders have no obligation to share in the losses of the Company.

Diluted earnings (loss) per share is calculated by dividing net income (loss) attributable to the Company’s ordinary shareholders as adjusted for the effect of dilutive ordinary share equivalents, if any, by the weighted average number of ordinary and dilutive ordinary share equivalents outstanding during the year. Ordinary share equivalents include the ordinary shares issuable upon the exercise of the outstanding share options (using the treasury stock method) and conversion of redeemable preferred shares and convertible bonds (using the as-if-converted method). Potential dilutive securities are not included in the calculation of diluted earnings (loss) per share if the impact is anti-dilutive.

(ee) Recently Adopted Accounting Standards

In November 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes. This ASU simplifies the presentation of deferred income taxes by requiring that all deferred tax liabilities and assets be classified as long-term on the balance sheet. The Company early adopted ASU 2015-17 in the fourth quarter of 2016 and prior periods were not retrospectively adjusted.

(ff) Recently Issued Accounting Standards

In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers, and has subsequently issued several supplemental and/or clarifying ASUs (collectively “ASC 606”). ASC 606 prescribes a single common revenue standard that replaces most existing U.S. GAAP revenue recognition guidance. ASC 606 outlines a five-step model, under which the Company will recognize revenue as performance obligations within a customer contract are satisfied. ASC 606 is intended to provide more consistent interpretation and application of the principles outlined in the standard across filers in multiple industries and within the same industries compared to current practices, which should improve comparability. ASC 606 is effective for public companies for fiscal years beginning after December 15, 2017. Upon adoption, the Company must elect to adopt either retrospectively to each prior reporting period presented or using the cumulative effect transition method with the cumulative effect of initial adoption recognized at the date of initial application. The Company is continuing to assess the effect of adoption by analyzing current portfolio of customer contracts, including a review of historical accounting policies and practices to identify potential differences in applying the guidance of ASC 606. Based on the preliminary review of its customer contracts, the Company expects that revenue on the majority of its customer contracts will continue to be recognized over time, consistent with its current revenue recognition model.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (‘‘ASU 2016-02’’). Under the new guidance, lessees will be required to recognize the following for all leases (with the exception of short-term leases) at the commencement date: (1) a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and (2) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. Under the new guidance, lessor accounting is largely unchanged. Certain targeted improvements were made to align, where necessary, lessor accounting with the lessee accounting model and Topic 606, Revenue from Contracts with Customers. The new lease guidance simplified the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. Lessees (for capital and operating leases) and lessors (for sales-type, direct financing, and operating leases) must apply a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The modified retrospective approach would not require any transition accounting for leases that expired before the earliest comparative period presented. Lessees and lessors may not apply a full retrospective transition approach. ASU 2016-02 is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, with early adoption permitted. While the Company is continuing to assess the effect of adoption, the Company currently believes the most significant changes relate to the recognition of right-of-use (“ROU”) assets and lease liabilities on our balance sheet for operating leases of the building of certain data centres. As of December 31, 2016, the Company had operating lease commitments expiring within 20 years from the inception of the lease. The amount of the Company’s future minimum lease payments under operating leases was RMB838,213 as of December 31, 2016.

In March 2016, the FASB issued ASU 2016-09, “Compensation - Stock Compensation (Topic 718),” which simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for public complies for fiscal years beginning after December 15, 2016. The Company is evaluating the impact that ASU 2016-09 will have on its consolidated financial statements and related disclosures.

In June 2016, the FASB issued ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326).” The amendments in this ASU replace the “incurred loss” methodology for recognizing credit losses with a methodology that reflects expected credit losses and requires consideration of a broader range of information including past events, current conditions and reasonable and supportable forecasts that affect the collectibility of reported amounts of financial assets that are not accounted for at fair value through net income, such as loans, certain debt securities, trade receivables, net investment in leases, off-balance sheet credit exposures and reinsurance receivables. Under the current GAAP incurred loss methodology, recognition of the full amount of credit losses is generally delayed until the loss is probable of incurring. Current GAAP restricts the ability to record credit losses that are expected, but do not yet meet the probability threshold. ASU 2016-13 becomes effective for public complies for fiscal years beginning after December 15, 2019. The Company is evaluating the impact that ASU 2016-13 will have on its consolidated financial statements and related disclosures.

In August 2016, the FASB issued ASU 2016-15, “Classification of Certain Cash Receipts and Cash Payments (Topic 230).” The new guidance is intended to reduce diversity in how certain transactions are classified in the consolidated statement of cash flows. ASU 2016-15 will be effective for public complies for fiscal years beginning after December 15, 2017. The Company is evaluating the impact that ASU 2016-15 will have on its consolidated financial statements and related disclosures.

In October 2016, the FASB issued ASU 2016-16, “Income Taxes (Topic 740), Intra-Entity Transfers of Assets Other Than Inventory.” ASU 2016-16 requires entities to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Current GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party. ASU 2016-16 will be effective for public complies for fiscal years beginning after December 15, 2017. The Company is evaluating the impact that ASU 2016-16 will have on its consolidated financial statements and related disclosures.

ACCOUNTS RECEIVABLES, NET

12 Months Ended

Dec. 31, 2016

ACCOUNTS RECEIVABLES, NET

ACCOUNTS RECEIVABLES, NET

3 ACCOUNTS RECEIVABLES, NET

Accounts receivables, net consisted of the following:

	As at December 31
	2015		2016

Accounts receivables	113,169		198,851
Less: allowance for doubtful accounts	(2,156	)	—


Accounts receivables, net	111,013		198,851

The Company generally invoices its customers on a monthly or quarterly basis in accordance with the contract terms. Due to the timing difference between the billing and revenue recognition, accounts receivables included an unbilled portion of RMB46,275 and RMB117,192 as of December 31, 2015 and 2016, respectively.

Accounts receivables of RMB42,511 and RMB87,347 was pledged as security for bank loans (note 10) as of December 31, 2015 and 2016, respectively.

An allowance for doubtful accounts is provided based on the Company’s best estimate of the amount of probable credit losses in the Company’s existing accounts receivable. The Company assesses the collectability of accounts receivable by analyzing specific customer accounts that have known or potential doubt as to collectability. The following table presents the movement of the allowance for doubtful accounts:

	Year ended December 31,
	2014	2015	2016

Balance at the beginning of the year	—	2,156	2,156
Allowance made during the year	2,156	—	—
Reversal during the year	—	—	(2,156	)

Balance at the end of the year	2,156	2,156	—

During the year ended December 31, 2016, the Company reversed allowance for doubtful accounts on a receivable from a customer of RMB 2,156 due to the collection of such balance during 2016. Management believes all other accounts receivable as of December 31, 2015 and 2016 are to be collected in full.

- Definition

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

OTHER CURRENT ASSETS

12 Months Ended

Dec. 31, 2016

OTHER CURRENT ASSETS

OTHER CURRENT ASSETS

4 OTHER CURRENT ASSETS

Other current assets consisted of the following:

	As at December 31
	2015	2016

Rental and other deposits	9,456	30,136
Deferred tax assets, current (note 20)	5,193	—
Assets held for sale	18,531	18,531
Others	508	484

	33,688	49,151

Assets held for sale included property held for sale of RMB9,075 and IT equipment awaiting for sale of RMB9,456, for which the Company has entered into sale contracts with the customer.

Others mainly represented miscellaneous receivables due from employees.

PROPERTY AND EQUIPMENT, NET

12 Months Ended

Dec. 31, 2016

PROPERTY AND EQUIPMENT, NET

PROPERTY AND EQUIPMENT, NET

5 PROPERTY AND EQUIPMENT, NET

Property and equipment consisted of the following:

	As at December 31, 2015		As at December 31, 2016

At cost:
Buildings	1,049,376		1,652,641
Data center equipment	891,089		1,349,069
Leasehold improvement	554,450		1,202,979
Furniture and office equipment	32,001		31,270
Vehicles	2,728		3,199


	2,529,644		4,239,158
Less: Accumulated depreciation	(421,475	)	(613,658	)


	2,108,169		3,625,500
Construction in progress	404,518		697,391


Property and equipment, net	2,512,687		4,322,891

(1)

The carrying amounts of the Company’s property and equipment acquired under capital leases and other financing arrangement at the respective balance sheet dates were as follows:

	As at December 31, 2015		As at December 31, 2016

At cost:
Buildings(note)	627,874		1,286,079
Data center equipment	12,718		26,375

	640,592		1,312,454
Less: Accumulated depreciation	(32,061	)	(64,151	)

	608,531		1,248,303

Note: This item included those buildings under construction, of RMB205,000 and RMB313,721, respectively, as of December 31, 2015 and 2016.

(2)

Depreciation of property and equipment (including assets acquired under capital leases and other financing arrangement) was RMB77,946, RMB135,864 and RMB212,873 for the years ended December 31, 2014, 2015 and 2016, respectively, and included in the following captions:

	Year ended December 31,
	2014	2015	2016

Cost of revenue	71,024	131,097	206,724
General and administrative expenses	6,922	4,767	5,425
Research and development expenses	—	—	724


	77,946	135,864	212,873

(3)

Property and equipment with net a book value of RMB579,524 and RMB512,566 was pledged as security for bank loans (note 10) as of December 31, 2015 and 2016, respectively.

(4)

As of December 31, 2015 and 2016, payables for purchase of property and equipment that are contractually due beyond one year of RMB 31,152 and RMB37,126 are recorded in other long-term liabilities in the consolidated balance sheets.

INTANGIBLE ASSETS, NET

12 Months Ended

Dec. 31, 2016

INTANGIBLE ASSETS, NET

INTANGIBLE ASSETS, NET

6 INTANGIBLE ASSETS, NET

Intangible assets consisted of the following:

	Note	As at December 31, 2015		As at December 31, 2016

Customer relationships	8	44,822		104,322
Favorable lease	8	15,500		15,500

		60,322		119,822
Less: accumulated amortization		(13,387	)	(27,253	)

Intangible assets, net		46,935		92,569

The Company’s customer relationships and favorable lease were acquired in business combinations (note 8).

Amortization of intangible assets was RMB4,462, RMB8,925 and RMB13,866 for the years ended December 31, 2014, 2015 and 2016, respectively.

Estimated future amortization expense related to these intangible assets is as follows:

Fiscal year ending December 31,
2017		16,939
2018		16,939
2019		16,939
2020		8,789
2021		8,789
Thereafter		24,174

Total		92,569

PREPAID LAND USE RIGHTS

12 Months Ended

Dec. 31, 2016

PREPAID LAND USE RIGHTS

PREPAID LAND USE RIGHTS

7 PREPAID LAND USE RIGHTS

Prepaid land use rights consisted of the following:

	As at December 31
	2015		2016

Prepaid land use rights	28,370		28,370
Less: Accumulated amortization	(962	)	(1,578	)

Prepaid land use rights, net	27,408		26,792

Amortization of prepaid land use rights was RMB 345, RMB 617 and RMB616 for the years ended December 31, 2014, 2015 and 2016, respectively.

Prepaid land use rights with a net book value of RMB20,983 and RMB20,735 were pledged as security for bank loans (note 10) as of December 2015 and 2016, respectively.

BUSINESS COMBINATION

12 Months Ended

Dec. 31, 2016

BUSINESS COMBINATION

BUSINESS COMBINATION

8 BUSINESS COMBINATION

The movement of goodwill is set out as below:

	As at December 31
	2015	2016

Balance at the beginning of the year	1,294,664	1,294,664
Addition during the year	—	46,423

Balance at end of year	1,294,664	1,341,087

Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in the acquisition. The goodwill is not deductible for tax purposes. Goodwill is assigned to the design, build-out and operation of data centers reporting unit.

EDC Holding Acquisition

Prior to the acquisition, the Company held a 7% non-controlling equity interest in EDC Holding which was accounted for under the cost method. EDC Holding is principally engaged in providing colocation services in the PRC.

On June 30, 2014, in an effort to enhance its service offering and to increase business synergy, the Company acquired all the equity interests in EDC Holding (preferred and ordinary shares) it did not already own, for a consideration comprising 88,352,558 ordinary shares and 110,810,606 redeemable preferred shares of the Company, consisting of 14,149,705 Series A* redeemable preferred shares (“Series A* Shares”), 33,959,293 Series B1 redeemable preferred shares (“Series B1 Shares”), 25,618,413 Series B2 redeemable preferred shares (“Series B2 Shares”), 14,045,432 Series B3 redeemable preferred shares (“Series B3 Shares”) and 23,037,763 Series B4 redeemable preferred shares (“Series B4 Shares”). The fair value of the consideration was determined by management with the assistance of a third party appraiser and was considered more reliably measured than the acquisition-date fair value of the acquiree’s equity interests.

Prior to the acquisition, the Company and EDC Holding had certain shareholders who held preferred shares in both companies with different ownership interests. None of these shareholders or any other ordinary or preferred shareholders individually or as a group acting in concert held more than 50% of the voting interest of each entity. The Company accounted for the business combination by applying the acquisition method of accounting. The Company completed the acquisition of EDC Holding on June 30, 2014, the date on which the consideration was transferred, and control was obtained to govern the financial and operating policies of EDC Holding and obtain benefits from its activities.

The Company was identified as the accounting acquirer for the following reasons: (i) the Company was the entity that issued the new equity interests; (ii) a shareholder of the Company held the largest minority voting interest in the combined entity; (iii) the Company’s shareholders have the ability to elect or appoint or to remove a majority of the members of the governing body of the combined entity; (iv) the Company’s management dominates the management of the combined entity after the acquisition; and (v) the Company has a significantly larger relative size in terms of revenue and operations than that of EDC Holding.

Total fair value of consideration transferred at acquisition date was as follows:

Fair value of ordinary shares issued		472,945
Fair value of redeemable preferred shares issued		711,297

Total fair value of total consideration transferred		1,184,242

The fair value of the ordinary shares issued was US$0.87 per share and the fair values of the various series of preferred shares issued ranged from US$0.93 to US$1.13 per share or on average approximately US$1.04 per share. Each series of preferred shares issued had different terms; in particular, the redemption amount of each series of preferred shares was different.

The identifiable assets acquired and liabilities assumed in the business combination were recorded at their fair value on the acquisition date and consisted of the following major items.

	Note
Fair value of consideration transferred		1,184,242
Fair value of non-controlling equity interest previously held by the Company	(i)	62,506

Sub-total		1,246,748

Effective settlement of pre-existing relationships	(ii)	549,521

Recognized amounts of identifiable assets acquired and liabilities assumed
Cash		(40,999	)
Property and equipment	(iii)	(1,535,246	)
Identifiable intangible assets	(iv)	(60,322	)
Other assets		(96,508	)
Short-term borrowings and current portion of long-term borrowings		178,638
Accounts payable		290,326
Obligations under capital leases, current		35,234
Long-term borrowings, excluding current portion		342,130
Deferred tax liabilities		45,748
Obligations under capital leases, non-current		250,318
Other liabilities		89,076

Total identifiable net assets		(501,605	)

Goodwill		1,294,664

Note (i):The gain of RMB62,506 arising from the re-measurement of the existing carrying value of investment in EDC Holding to fair value was recognized in the consolidated statement of operations. The fair value of the previous held non-controlling equity interest was determined by management with the assistance of a third party appraiser.

Note (ii):Prior to the business combination, the Company had the following pre-existing relationships with EDC Holding: (1) a prepayment due from EDC Holding of RMB254,633 for future services under a service contract with EDC Holding; (2) outstanding loans of RMB344,110 due from EDC Holding; and (3) a loan of US$8,000 (RMB49,222) issued from EDC Holding to the Company in January 2013. No gain or loss was recognized from the effective settlement of such pre-existing relationship between the Company and EDC Holding. At the acquisition date, the amount due from EDC Holding of RMB598,743 and the amount due to EDC Holding of RMB49,222 are eliminated upon consolidation.

Note (iii):Property and equipment acquired included data center buildings of RMB624,090, properties acquired under capital lease of RMB422,874, data center equipment of RMB299,801, leasehold improvement of RMB2,694, furniture and office equipment of RMB958, vehicles of RMB749 and construction in progress of RMB184,080.

Note (iv):Identifiable intangible assets acquired consisted of customer relationships of RMB44,822 with an estimated useful life of 5 to 6 years and favorable lease of RMB15,500 with estimated useful life of 20 years.

The amounts of net revenue and net loss of EDC Holding included in the Company’s consolidated statements of operations from the acquisition date to December 31, 2014 amounted to RMB17,880 and RMB99,949, respectively.

Guangzhou Weiteng Acquisition

On May 19, 2016, the Company acquired all of the equity interests in Guangzhou Weiteng Construction Co., Ltd. (“WTENG”) from a third party for an aggregate purchase price of RMB129,500. In May 2016, the Company paid consideration of RMB103,600 and the remaining consideration of RMB25,900 will be paid by May 19, 2017. WTENG is a limited liability company organized and existing under the PRC law and owns a data center in Guangzhou. At the date of acquisition, the data center has just commenced its operations.

The identifiable assets acquired and liabilities assumed in the business combination were recorded at their fair value on the acquisition date and consisted of the following major items.

	Note
Fair value of consideration		129,500
Effective settlement of pre-existing relationships upon consolidation	(i)	43,161
Recognized amounts of identifiable assets acquired and liabilities assumed
Cash		(1,237	)
Property and equipment	(ii)	(281,437	)
Identifiable intangible assets	(iii)	(59,500	)
Other assets		(25,363	)
Accounts payable		131,114
Capital lease and other financing obligations, current		12,097
Capital lease and other financing obligations, non-current		68,584
Deferred tax liabilities		21,143
Other liabilities		8,361

Total identifiable net assets		(126,238	)

Goodwill	(iv)	46,423

Note (i):Prior to the acquisition of WTENG, in February and May 2016, the Company lent short-term loans of RMB40,000 and RMB2,000, respectively, to WTENG. The loans bear an interest rate of 10% per annum and mature in September 2016. No gain or loss was recognized from the effective settlement of such pre-existing relationship between the Company and WTENG. At the acquisition date, the amount due from WTENG of RMB 43,161, including loan principal of RMB42,000 and interest receivable of RMB1,161, is eliminated upon consolidation.

Note (ii):Property and equipment acquired included properties and equipment acquired under capital lease and other financing arrangement of RMB102,785, data center equipment of RMB19,895, leasehold improvement of RMB132,462 and construction in progress of RMB26,295.

Note (iii):Identifiable intangible assets acquired consisted of customer relationships of RMB59,500 with an estimated useful life of 7 to 8 years.

Note (iv):Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in the acquisition of WTENG. Goodwill is assigned to the design, build-out and operation of data centers reporting unit. Goodwill primarily represents the expected synergies from combining operations of WTENG with those of the Company and intangible assets that do not qualify for separate recognition and is not deductible for tax purposes. In accordance with ASC350, goodwill is not amortized but is tested for impairment.

The amounts of net revenue and net loss of WTENG included in the Company’s consolidated statements of operations from the acquisition date to December 31, 2016 amounted to RMB36,924 and RMB2,861, respectively.

Supplemental pro forma financial information as if acquisition had occurred as of the earliest date presented has not been provided as WTENG acquisition is not material to the Company’s results of operations.

- Definition

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1497-128463

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1490-128463

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7008-128479

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1486-128463

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4845-128472

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1524-128463

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7000-128479

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4922-128472

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4934-128472

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4926-128472

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 4A
-URI http://asc.fasb.org/extlink&oid=73530397&loc=SL65897772-128472

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1383-128463

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6996-128479

+ Details

OTHER NON-CURRENT ASSETS

12 Months Ended

Dec. 31, 2016

OTHER NON-CURRENT ASSETS

OTHER NON-CURRENT ASSETS

9 OTHER NON-CURRENT ASSETS

Other non-current assets consisted of the following:

	As at December 31
	2015	2016

Deposits for leases	46,423	62,985
Other deposits	—	15,000
Others	11,093	20,740

	57,516	98,725

Deposits for leases amounted to RMB46,423 and RMB62,985 as of December 31, 2015 and 2016, respectively, which are expected to be refunded after one year of the balance sheet date at the end of the lease term. Deposits for leases, which are expected to be refunded within one year of the balance sheet date, are recorded in other current assets.

In April 2016, the Company entered into a memorandum of understanding (MOU) with a third party in respect of a potential acquisition of a data center and paid a deposit of RMB15,000 to such third party. The final purchase price and other major terms of the acquisition have not yet been agreed, as negotiations are still in process and due diligence has not been completed. The deposit amount may be deducted from the final purchase price if the acquisition is consummated. According to the terms of the MOU, as amended, if the acquisition is not consummated within 24 months of the date of the MOU, RMB5,000 of the deposit amount will be refunded to the Company and the remainder will be forfeited.

LOANS AND BORROWINGS

12 Months Ended

Dec. 31, 2016

LOANS AND BORROWINGS

LOANS AND BORROWINGS

10 LOANS AND BORROWINGS

The Company’s borrowings consisted of the following:

	As at December 31, 2015	As at December 31, 2016

Short-term borrowings	333,000	239,777
Current portion of long-term borrowings	95,218	388,701

Sub-total	428,218	628,478
Long-term borrowings, excluding current portion	958,264	1,509,676

Total loans and borrowings	1,386,482	2,138,154

Short-term borrowings

The Company’s short-term borrowings consisted of the following:

	As at December 31, 2015	As at December 31, 2016

Unsecured short-term loans and borrowings	60,000	—
Secured short-term loans and borrowings	273,000	239,777

	333,000	239,777

(i) Short-term borrowings were secured by the following assets:

	As at December 31, 2015	As at December 31, 2016

Accounts receivable	20,221	19,914
Property and equipment, net	144,540	—
Prepaid land use rights, net	14,602	—

	179,363	19,914

(ii)The weighted average interest rates of short-term borrowings were 6.98%, 6.55% and 5.27% per annum for the years ended December 31, 2014, 2015 and 2016, respectively.

(iii)Short-term loans of RMB 247,000 and RMB nil as of December 31, 2015 and 2016, respectively, are guaranteed by William Wei Huang, Director and CEO of the Company.

Long-term borrowings

The Company’s long-term borrowings consisted of the following:

	As at December 31, 2015	As at December 31, 2016

Unsecured long-term loans and borrowings	2,844	—
Secured long-term loans and borrowings	1,050,638	1,898,377



	1,053,482	1,898,377

(i) The weighted average interest rates of long-term borrowings were 10.2%, 8.73% and 8.16% per annum for the years ended December 31, 2014, 2015 and 2016, respectively.

(ii) Long-term borrowings were secured by the following assets:

	As at December 31, 2015	As at December 31, 2016

Accounts receivable	22,290	67,433
Property and equipment, net	434,984	512,566
Prepaid land use rights, net	6,381	20,735

	463,655	600,734

(iii) Long-term loans of RMB 194,955 and RMB9,500 as of December 31, 2015 and 2016 are guaranteed by William Wei Huang.

(iv) The aggregate maturities of the above long-term borrowings for each for the five years and thereafter subsequent to December 31, 2016 are as follows:

		Long-term borrowings
Twelve-months ending December 31 ,
2017		388,701
2018		324,473
2019		385,388
2020		359,179
2021		412,457
Thereafter		28,179


		1,898,377

As of December 31, 2015 and 2016, the particulars of the total secured long-term loans and borrowings of RMB1,050,638 and RMB1,898,377 and the related facilities, were as follows:

i) In 2009, a subsidiary of the Company entered into a thirteen-year entrusted credit facility for a principal amount of RMB322,000 with the local government through a third party bank. As of December 31, 2015 and 2016, the outstanding loan under such credit facility was RMB225,400 and RMB189,179, respectively, and the effective interest rate of the loan was 4.9% per annum. The facility was secured by prepaid land use right with a carrying amount of RMB6,235 as of December 31, 2016 (2015: RMB6,381).

ii) In 2014, a subsidiary of the Company entered into an entrusted credit facility of RMB200,000 with a third party lender through a third party bank. As of December 31, 2015 and 2016, the outstanding loan under such credit facility was RMB199,800 and RMB199,600, respectively, and the effective interest rate of the loan was 18% per annum. The facility was secured by accounts receivables with a carrying amount of RMB13,367 as of December 31, 2016 (2015: RMB22,290). The loan contains financial covenants, which require that the subsidiary’s outstanding loans (exclusive of this entrusted loan and any other entrusted loans) should be within a range of RMB130,000 and RMB240,000 (the “borrowing range”) and the total pledged assets not exceeding RMB20,000. On March 31, 2015, the subsidiary’s outstanding loans exceeded RMB240,000 and total pledged assets exceeded RMB20,000. On June 10, 2015, the subsidiary obtained a waiver letter from the creditor that waived the covenant violations. The creditor and the subsidiary also agreed to revise the acceptable outstanding borrowings in a range of RMB130,000 and RMB360,000 and removed the restriction on the pledged assets. As of December 31, 2016, the Company was in compliance with such covenants.

iii) In 2015, a subsidiary of the Company entered into a six-year credit facility with a third party bank amounting to RMB290,000. The facility is guaranteed by William Wei Huang, Director and CEO of the Company and secured by property and equipment with carrying amount value of RMB154,178 as of December 31, 2015. The effective interest rate of the loan was 5.94% per annum. As of December 31, 2015, the outstanding loan under such credit facility was RMB180,455 and the Company fully repaid the outstanding loan in 2016.

iv) In 2015 and 2016, two subsidiaries of the Company entered into loan facilities with third party banks in the aggregate amount of RMB650,000. As of December 31, 2015 and 2016, the outstanding loans under such credit facilities were RMB380,483 and RMB415,048 (net of debt issuance costs), respectively, and the effective interest rate of the loans was 6.56%-6.83% and 7.72%-7.82% per annum as of December 31, 2015 and 2016, respectively. The outstanding loans under such credit facilities are secured by accounts receivables and property and equipment with a carrying amount of RMB13,305 and RMB153,653 as of December 31, 2016 (2015: nil and RMB142,386, respectively). The outstanding loans contain a limit on the amount of capital expenditures to be incurred for the construction of the data centers and mature in 2020. The outstanding loans are required to be repaid in full prior to the maturity date in the event 1) Singapore Technologies Telemedia Limited of Singapore, the parent company of STT GDC Pte. Ltd. (a principal shareholder of the Company), ceases to own and control, directly or indirectly, at least 40% of the equity interest in the Company prior to an initial public offering (IPO) or 30% of the equity interest in the Company after an IPO, or ceases to be the single largest shareholder of the Company, (2) the Company ceases to own and control, directly or indirectly, 100% of the equity interest of the borrowing subsidiaries, (3) there are changes in the shareholding structure of a principal operating subsidiary, as defined in the loan agreements or (4) William Wei Huang, the founder, chairman and chief executive officer of the Company, ceases to own and control, directly or indirectly, at least 99.96% of the equity interest of GDS Beijing. In addition, under the terms of the loans, upon the completion of the Company’s IPO, the Company is required to repay RMB139,232 of the outstanding loan principal amount based on the principal amount outstanding as of completion date of IPO. The loan facilities contain financial covenants that limit certain financial ratios, such as the interest coverage ratio and gross leverage ratio, during the relevant period, as defined in the facilities. The loan facilities include a cross- default provision which would be triggered if the Company fails to repay any financial indebtedness of RMB30,000 or more when due or within any originally applicable grace period. After the completion of IPO, the Company fully repaid RMB99,232 of the outstanding loan principal in December 2016 and the remaining RMB40,000 in March 2017 as agreed with the banks. As of December 31, 2016, the Company was in compliance with these covenants.

v) In September 2016, two subsidiaries of the Company entered into loan facilities with third party banks in a total amount of RMB1,135,000, for the purpose of (i) replacing an existing term loan facility agreement entered into in June 2016, and (ii) financing the subsidiaries’ data center projects and working capital requirements. As of December 31, 2016, the outstanding loan under such facility was RMB866,983, consisting of a short term working capital loan of RMB12,629 with an effective interest rate of 5.66% per annum and long term loans of RMB854,354 (net of debt issuance costs) with effective interest rates of 7.02%-7.34% per annum. The outstanding loans under such facilities are secured by accounts receivables and property and equipment with a carrying amount of RMB8,185 and RMB110,831 as of December 31, 2016, respectively. The loans are required to be repaid in full prior to the maturity date in the event (i) STT Communications Ltd. ceases to, directly or indirectly, own at least 50.1% of equity interests of STT GDC, (ii) STT GDC ceases to own and control, directly or indirectly, at least 40% of the equity interests in the Company prior to an IPO or 30% of the equity interests in the Company after an IPO, or ceases to be the single largest shareholder of the Company, (iii) the Company ceases to, directly or indirectly, own or control 100% of the borrowing subsidiary, (iv) there are changes in the shareholding structure of a principal operating subsidiary, as defined in the loan agreement or (v) William Huang ceases to, directly or indirectly, own at least 99.9% of the equity interests of GDS Beijing ((i), (ii), (iii), (iv) and (v) are referred to as “the Early Repayment Events”). The loan facilities contain financial covenants that limit certain financial ratios, such as the interest coverage ratio and gross leverage ratio, during the relevant period, as defined in the facilities. In addition, the loan facility includes a cross default provision which would be triggered if the Company fails to repay any financial indebtedness in an aggregate amount of RMB50,000 or more when due or within any originally applicable grace period. The outstanding long-term loans mature in 2021. As of December 31, 2016, the Company was in compliance with these covenants.

vi) In September 2016, a subsidiary of the Company entered into a facility agreement with a third party bank for a total amount of RMB220,000. As of December 31, 2016, the outstanding loan under such facility was RMB137,334, consisting of a short term working capital loan of RMB12,611 with an effective interest rate of 5.87% per annum and long term loans of RMB124,723 (net of debt issuance costs) with an effective interest rate of 7.63% per annum. The outstanding loans under such facilities are secured by accounts receivable and property and equipment with a carrying value of RMB30,110 and RMB85,765 as of December 31, 2016, respectively. The loans are required to be repaid in full prior to the maturity date upon the occurrence of any of the Early Repayment Events. The loan facilities contain financial covenants that limit certain financial ratios, such as the interest coverage ratio and gross leverage ratio, during the relevant period, as defined in the facilities. In addition, the loan facility includes a cross default provision which would be triggered if the Company fails to repay any financial indebtedness in an aggregate amount of RMB50,000 or more when due or within any originally applicable grace period. The outstanding long-term loans mature in 2021. As of December 31, 2016, the Company was in compliance with these covenants.

vii) In December 2016, a subsidiary of the Company entered into a facility agreement with third party banks, pursuant to which the bank agrees to make available to the subsidiary loan facilities in the total amount of RMB380,000 for repayment of borrower’s outstanding loan and financing borrower’s data center located in Beijing. The interest rate agreed under the facility agreement is the aggregate of the applicable 3.65% per annum and SHIBOR, as defined in the facility agreement, with a term of up to eighteen months from first facility utilization date. The securities for the loan include, among others, the subsidiaries’ receivables and property and equipment. The loans are required to be repaid in full prior to the maturity date upon the occurrence of any of the Early Repayment Events. The loan facilities contain financial covenants that limit certain financial ratios, such as the interest coverage ratio and gross leverage ratio, during the relevant period, as defined in the facilities. In addition, the loan facility includes a cross default provision which would be triggered if the borrower fails to repay any financial indebtedness in an aggregate amount of RMB30,000 or more when due or within any originally applicable grace period. As of December 31, 2016, the Company did not draw down any amount under such facility.

viii) In December 2016, a subsidiary of the Company entered into a facility agreement with third party banks for a total amount of RMB310,000. As of December 31, 2016, the outstanding loan under such facility was RMB106,510, consisting of a short term working capital loan of RMB537 with an effective interest rate of 5.66% per annum and long term loans of RMB105,973 (net of debt issuance costs) with an effective interest rate of 6.32% per annum. The outstanding loans under such facilities are secured by accounts receivable, property and equipment and prepaid land use right with a carrying value of RM2,466, RMB138,941 and RMB14,500 as of December 31, 2016, respectively. The loans are required to be repaid in full prior to the maturity date upon the occurrence of any of the Early Repayment Events. The loan facilities contain financial covenants that limit certain financial ratios, such as the interest coverage ratio and gross leverage ratio, during the relevant period, as defined in the facilities. In addition, the loan facility includes a cross default provision which would be triggered if the Company fails to repay any financial indebtedness in an aggregate amount of RMB50,000 or more when due or within any originally applicable grace period. The outstanding long-term loans mature in 2021. As of December 31, 2016, the Company was in compliance with these covenants.

ix) As of December 31, 2015 and 2016, secured long-term loans and borrowings amounted to RMB64,500 and RMB9,500, respectively. The loans mature in 2017, are secured by property and equipment with carrying amount of RMB138,420 and RMB23,376 as of December 31, 2015 and 2016, respectively, and do not contain any financial covenants. In addition, as of December 31, 2015 and 2016, RMB 14,500 and RMB9,500 was guaranteed by William Wei Huang, Director and CEO of the Company and the effective interest rates of the outstanding loan was 5.39%~6.46% and 5.39% per annum, respectively.

As of December 31, 2015 and 2016, the particulars of unsecured long-term loans and borrowings are as follows:

i) In 2014, a subsidiary of the Company entered into a two-year credit facility with a third party bank amounting to US$5,000. As of December 31, 2015, the outstanding loan under such credit facility was RMB2,844 (US$438). In 2016, the Company fully repaid the loan.

As of December 31, 2016, the Company has total working capital and project financing credit facilities of RMB3,181,278 from various banks, of which the unused amount was RMB968,878. As of December 31, 2016, the Company drew down RMB2,212,400, of which RMB239,777 was recorded in short-term loans and borrowing and RMB1,898,377 (net of debt issuance costs of RMB74,246) was recorded in long-term loans and borrowing, respectively. Draw downs from the credit facility are subject to the approval of the banks and are subject to the terms and conditions of each agreement.

BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE

12 Months Ended

Dec. 31, 2016

BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE

BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE

11 BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE

Bonds due June 10, 2014 issued by a subsidiary (“Bonds due 2014”)

On December 11, 2012, the Company issued Bonds due 2014 to an investor in an aggregate principal amount of US$10,509 (RMB66,125). The Bonds due 2014 had a maturity date of June 10, 2014 and carried interest at 10% per annum. Upon maturity, the carrying amount of the Bonds due 2014 was US$10,509 (RMB64,541) and the Company repaid a portion of the Bonds due 2014 amounting to US$664 (RMB4,081). On June 11, 2014, the Company issued Bonds due 2015 to the same investor in an aggregate principal amount of US$30,203 (RMB185,770) of which a portion was to settle the remaining unpaid portion of the Bonds due 2014 of US$9,845 (RMB60,460) and unpaid interest payable on the Bonds due 2014 of RMB10,360.

Bonds due June 10, 2015 issued by the Company (“Bonds due 2015”)

The key terms of the Bonds due 2015 are summarized as follows:

Denomination

Denomination—US$10 each

Maturity date

Maturity date—June 10, 2015

Interest rate and interest repayment

Interest rate is at 10% per annum compounded annually.

Redemption and price

The Company shall redeem the unpaid principal together with the interest accrued of the Bonds due 2015 on the Maturity Date

Exchange feature of the Bonds due 2015

Prior to the Maturity Date, the holder of Bonds due 2015 has the right to exchange the bonds into the Company’s ordinary shares in the event of a qualifying initial public offering (“QIPO”) or private placement. The exchange feature permits the holder to receive a variable number of ordinary shares with an aggregate fair value that is based on a fixed monetary amount (the principal amount of the Bonds due 2015 that is being exchanged). The price used to determine the number of ordinary shares issued in exchange for the bonds is equal to 70% of the QIPO price or 70% of the share issuance price of the private placement. The Company separated this contingent redemption exchange feature (or embedded put option) from the principal amount of the Bonds due 2015 at the issuance date. The fair value of the embedded put option was US$5,547 (RMB34,105). The recorded discount resulting from the allocation of the proceeds of the Bonds due 2015 to this embedded put option was recognized as interest expense. As of December 31, 2015, there was no outstanding embedded derivative due to the holder’s exercise of the right to exchange a portion of the Bonds due 2015 following the completion of Series C shares in August 2014 and the holder waiving the right to exchange the remaining portion for ordinary shares described below. Total interest expense related to the debt discount amounted to RMB34,105 for the year ended December 31, 2014.

In August 2014, the Company conducted a private placement of 238,526,241 Series C redeemable preferred shares (“Series C Shares”) (note 15). Upon the issuance of Series C Shares, the holder of the Bonds due 2015 exchanged outstanding principal amount of the Bonds due 2015 of US$27,860 (RMB171,431) for 38,397,655 ordinary shares. The number of ordinary shares issued was based on US$0.72557, or 70% of the issuance price of Series C Shares of US$1.036522. The difference between the fair value of the ordinary shares and the principal amount of the bonds was RMB34,105, which as charged against the embedded put option described above. The holder waived its right to exchange the remaining Bonds due 2015 of US$2,343 (RMB14,330) for ordinary shares of the Company.

On June 10, 2015, the Company fully redeemed the remaining Bonds due 2015 of US$2,343 (RMB14,330) upon maturity.

Convertible Bonds due December 30, 2019 issued by the Company (“Convertible Bonds due 2019”)

On December 30, 2015, the Company entered into a subscription agreement with two investors (referred to as “PA investor” and STT GDC Pte. Ltd or “STT GDC”) for Convertible Bonds due 2019 in an aggregate principal amount of US$250,000 in four tranches. On December 30, 2015 and January 29, 2016, the Company received the first tranche of US$100,000 (RMB648,950) from PA investor and the second tranche of US$50,000 (RMB324,475) from STT GDC, respectively. The subscription for the remaining third and fourth tranches of the Convertible Bonds due 2019 in the aggregate principal amount of US$100,000 (RMB648,950) expired on September 30, 2016.

Convertible Bonds due 2019 bears an interest rate of 10% per annum and matures on December 30, 2019 (“Maturity Date”). The Company shall redeem the unpaid principal together with the interest accrued of the Convertible Bonds due 2019 on the December 30, 2019. As of December 31, 2016, accrued interests of RMB1,118 and RMB73,681 were recorded in accrued expenses and other payables and other long-term liabilities, respectively, of which RMB1,090 and RMB23,403 were due to STT GDC Pte. Ltd. The Company pledged 100% of the equity interests in a subsidiary to the investors.

The key terms of the Convertible Bonds due 2019 are summarized as follows:

Conversion of the Convertible Bonds due 2019

If the Company completes a QIPO, the bond holder, at any time between the date of completion of such QIPO (the “QIPO Completion Date”) and the Maturity Date (the “Conversion Period”), have the right to convert up to 100% of the principal amount of the bond (in multiples of US$10,000), together with the accrued interest thereon, into ordinary shares of the Company. The conversion price shall be US$1.675262 subject to adjustments for situations such as share dividend, share split, consolidation, recapitalization, exchange or substitution of ordinary shares at any time or from time to time. The Company determined that there was no embedded beneficial conversion feature (“BCF”) attributable to Convertible Bonds due 2019 at the commitment date because the initial conversion price of Convertible Bonds due 2019 was greater than the estimated fair value of the Company’s ordinary shares as of December 30, 2015. The estimated fair value of the underlying ordinary shares on December 30, 2015 was determined by management with the assistance of an independent valuation firm. The valuation used an income approach, which requires the estimation of future cash flows and the application of an appropriate discount rate with reference to comparable listed companies engaged in a similar industry to convert such future cash flows to a single present value.

The Company determined that the embedded conversion option of the Convertible Bonds due 2019 was not required to be accounted for as an embedded derivative for periods prior to the Company’s IPO, as the underlying ordinary shares were not publicly traded or otherwise readily convertible into cash. Upon the listing of the Company’s ordinary shares on November 2, 2016, the embedded conversion option has been accounted for separately as an embedded derivative with changes in its fair value recognized through the consolidated statement of operations. With the assistance of an independent appraiser, the Company determined that the fair value of the embedded conversion feature as a derivative liability was immaterial as of November 2, 2016 and December 31, 2016. Accordingly, no gain or loss was recognized in respect of the change in the fair value of such derivative liability for the year ended December 31, 2016.

If the Company completes a QIPO and the closing price of its shares is at or above 125% of the conversion price (i.e. 25% premium to the conversion price) for a period of at least ten consecutive trading days, the Company may, at its unilateral option, notify the bondholder that the bond then outstanding will be mandatorily converted at the end of the notice period in accordance with the terms and conditions of the bond.

Redemption on maturity:

Unless previously converted or purchased and cancelled in the circumstances, the bond will be redeemed on December 30, 2019 at its principal amount, plus accrued interest thereon.

ACCRUED EXPENSES AND OTHER PAYABLES

12 Months Ended

Dec. 31, 2016

ACCRUED EXPENSES AND OTHER PAYABLES

ACCRUED EXPENSES AND OTHER PAYABLES

12 ACCRUED EXPENSES AND OTHER PAYABLES

Accrued expenses and other payables consisted of the following:

	As at December 31
	2015	2016

Accrued rental expenses	12,951	12,744
Accrued utility expenses	8,548	14,348
Accrued payroll and welfare benefits	27,062	31,165
Accrued interest expenses	23,722	67,324
Accrued professional service fees	8,352	11,867
Other taxes payables	14,296	11,470
Income tax payable (note 20)	8,955	15,265
Consideration payable for the acquisition of WTENG (note 8)	—	25,900
Other payables	14,430	17,867

	118,316	207,950

Other payables represent amounts due to service providers for various services received by the Company.

LEASE

12 Months Ended

Dec. 31, 2016

LEASE

LEASE

13 LEASE

Capital lease and other financing obligations

The Company’s capital lease and other financing obligations are summarized as follows:

	December 31, 2015					December 31, 2016
	Capital lease obligations		Other financing obligations	Total		Capital lease obligations		Other financing obligations		Total
Within 1 year	51,591		—	51,591		71,300		22,044		93,344
After 1 year but within 2 years	60,019		—	60,019		85,783		38,443		124,226
After 2 years but within 3 years	64,938		—	64,938		92,677		39,548		132,225
After 3 years but within 4 years	69,089		—	69,089		193,202		41,586		234,788
After 4 years but within 5 years	172,079		—	172,079		71,501		42,287		113,788
After 5 years	395,251		—	395,251		716,089		725,178		1,441,267


Total	812,967		—	812,967		1,230,552		909,086		2,139,638

Less total future interest	(339,283	)	—	(339,283	)	(552,060	)	(450,670	)	(1,002,730	)
Less: estimated building costs	—		—	—		—		(25,356	)	(25,356	)


Present value of lease and other financing obligations	473,684		—	473,684		678,492		433,060		1,111,552

Including:
Current portion				48,745						88,593

Non-current portion				424,939						1,022,959

The Company’s capital and build-to-suit leases expire at various dates ranging from 2020 to 2035. The weighted average effective interest rate of the Company’s capital and build-to-suit leases was 9.71%, 8.63% and 8.04% as of December 31, 2014, 2015 and 2016, respectively.

During the years ended December 31, 2015 and 2016, the Company entered into the following lease arrangements:

Shenzhen 2 Lease and Shenzhen 3 Lease

In March 2015 and July 2015, the Company entered into two lease agreements to lease two existing buildings in Shenzhen, China from a third party lessor (the “Shenzhen 2 Lease” and the “Shenzhen 3 Lease”). The Shenzhen 2 Lease has a lease term of 10 years from June 2015 to May 2025 and the Shenzhen 3 Lease has a lease term of 15 years from November 2015 to October 2030. The Company determined that both leases were capital leases as the present value of the minimum lease payments of each of the leases exceeded 90% of the respective fair value of the leased property at the inception of the lease.

Accordingly, on the respective lease commencement date, the Company recorded capital lease assets and capital lease obligations at an amount equal to the present value of the minimum lease payments in the aggregate amount of RMB205,000.

Shenzhen 4 Lease

In October 2015, the Company entered into a lease agreement to lease an existing building in Shenzhen, China from a third party lessor (the “Shenzhen 4 Lease”). The Shenzhen 4 Lease has a lease term of 20 years commencing from January 2016. At the inception of the lease, Company determined that Shenzhen 4 Lease is a capital lease as the present value of the minimum lease payments exceeded 90% of the fair value of the leased property. In January 2016, the Company took possession of or controlled the physical use of the building from the lessor. Accordingly, in January 2016, the Company records a capital lease asset and a capital lease obligation at an amount equal to the present value at the beginning of the lease term of minimum lease payments during the lease term (or RMB138,721) on the lease commencement date.

Build-to-suit leases

In January and February 2015, the Company entered into two lease agreements with a third party developer-lessor for the development, construction and the lease (build-to-suit lease) of two brand new buildings (the “Shanghai 3 Lease” and “Shanghai 4 Lease”) in Shanghai, China. The Company paid a deposit for each of the two leases to the developer-lessor. Both the Shanghai 3 Lease and Shanghai 4 Lease have a lease term of 20 years commencing upon the delivery of the completed building to the Company. The two buildings will be constructed based on the Company’s specifications and will not include any interior elements, such as electrical wiring, interior walls, ventilation and air conditioning systems, flooring or normal tenant improvements. That is, the developer-lessor will hand over two cold-shell buildings to the Company upon completion of construction. Upon the delivery of the cold-shell buildings, the Company will convert the two buildings into data centers. No rent is paid by the Company during the construction of the two buildings. All project hard costs are to be paid by the developer-lessor, including site preparation and construction costs. In the event of termination of the lease agreements during the lease term, the Company is obligated to pay 15% of the total minimum lease payments. In addition, if the Company terminates the agreements before the construction of the buildings are completed, the Company is obligated to reimburse the developer-lessor for costs incurred during the construction period, including but not limited to project application costs, project design fees, ground preparation and leveling costs.

In accordance with ASC 840-40-55, the Company has determined that it is the owner of the two buildings during the construction period for financial reporting purposes as it has substantially all of the construction period risks based on the maximum guarantee test (without considering probability that the Company having to make the payments). Accordingly, the Company records an asset for the estimated incurred construction costs of the project and a liability for those costs funded by the lessor-developer during the construction period.

Upon completion of the construction and commencement of the lease terms, the Company assesses whether these arrangements qualify for sales recognition under the deemed sale-leaseback transaction. If the arrangements do not qualify for sales recognition under the sale-leaseback accounting guidance, the Company continues to be the deemed owner of the build-to-suit assets for financial reporting purposes. The Company keeps the construction costs of the assets on its balance sheet. In addition, lease payments less the portion considered to be interest expense decrease the financing liability.

Operating leases

The Company leases data centers, offices and other equipment that are classified as operating leases. The majority of the Company’s operating leases expire at various dates though 2035.

Future minimum operating lease payments as of December 31, 2016 are summarized as follow:

Twelve-months ending December 31,
2017		124,293
2018		98,566
2019		75,657
2020		57,268
2021		36,822
Thereafter		445,607

Total		838,213

Rental expenses were approximately RMB110,117, RMB131,875 and RMB124,712 for the years ended December 31, 2014, 2015 and 2016, respectively. The Company did not sublease any of its operating leases for the periods presented.

Other long-term liabilities

12 Months Ended

Dec. 31, 2016

Other long-term liabilities

Other long-term liabilities

14 Other long-term liabilities

Other long-term liabilities consisted of the following:

	As at December 31, 2015	As at December 31, 2016

Payables for purchase of property and equipment	31,152	37,126
Accrued interests	25,810	51,112
Deferred government grants	16,268	14,051
Others	5,775	9,417

Total	79,005	111,706

REDEEMABLE PREFERRED SHARES

12 Months Ended

Dec. 31, 2016

REDEEMABLE PREFERRED SHARES

REDEEMABLE PREFERRED SHARES

15 REDEEMABLE PREFERRED SHARES

	Series A				Series A*				Series B				Series B1				Series B2				Series B3				Series B4				Series B5				Series C				Total
	Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000
Balance at January 1, 2014	63,250,000		198,434		—		—		11,550,000		64,056		—		—		—		—		—		—		—		—		—		—		—		—		74,800,000		262,490
Issuance of redeemable preferred shares
—in relation to business combination	—		—		14,149,705		80,965		—		—		33,959,293		236,108		25,618,413		165,506		14,045,432		85,554		23,037,763		143,164		—		—		—		—		110,810,606		711,297
—third party investor	—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		238,526,241		1,501,167		238,526,241		1,501,167
Extinguishment of redeemable preferred shares upon repurchase	(23,533,064	)	(76,473	)	(5,503,899	)	(31,497	)	(8,413,412	)	(48,593	)	(13,209,358	)	(91,847	)	(9,964,954	)	(64,383	)	(5,463,340	)	(33,281	)	(8,961,143	)	(55,692	)	—		—		—		—		(75,049,170	)	(401,766	)
Extinguishment of redeemable preferred shares upon exchange	(10,081,891	)	(32,803	)	(1,729,161	)	(9,896	)	(560,105	)	(3,276	)	(9,222,193	)	(63,800	)	(5,217,820	)	(33,540	)	(8,582,092	)	(52,268	)	—		—		35,393,262		225,198		—		—		—		29,615
Changes in redemption value	—		6,824		—		—		—		2,393		—		—		—		—		—		—		—		—		—		5,210		—		54,689		—		69,116
Foreign exchange impact	—		1,292		—		3		—		500		—		(313	)	—		(164	)	—		(5	)	—		5		—		(725	)	—		(8,473	)	—		(7,880	)

Balance at December 31, 2014 and January 1, 2015	29,635,045		97,274		6,916,645		39,575		2,576,483		15,080		11,527,742		80,148		10,435,639		67,419		—		—		14,076,620		87,477		35,393,262		229,683		238,526,241		1,547,383		349,087,677		2,164,039
Changes in redemption value	—		4,029		—		—		—		754		—		—		—		—		—		—		—		—		—		13,715		—		92,428		—		110,926
Foreign exchange impact	—		6,125		—		—		—		955		—		—		—		—		—		—		—		—		—		14,640		—		98,629		—		120,349

Balance at December 31, 2015 and January 1, 2016	29,635,045		107,428		6,916,645		39,575		2,576,483		16,789		11,527,742		80,148		10,435,639		67,419		—		—		14,076,620		87,477		35,393,262		258,038		238,526,241		1,738,440		349,087,677		2,395,314
Changes in redemption value	—		(39,098	)	—		—		—		(3,921	)	—		—		—		—		—		—		—		—		—		(21,016	)	—		(141,635	)	—		(205,670	)
Conversion to ordinary shares	(29,635,045	)	(72,965	)	(6,916,645	)	(43,564	)	(2,576,483	)	(13,600	)	(11,527,742	)	(88,221	)	(10,435,639	)	(74,209	)	—		—		(14,076,620	)	(96,287	)	(35,393,262	)	(248,455	)	(238,526,241	)	(1,673,831	)	(349,087,677	)	(2,311,132	)
Foreign exchange impact	—		4,635		—		3,989		—		732		—		8,073		—		6,790		—		—		—		8,810		—		11,433		—		77,026		—		121,488

Balance at December 31, 2016	—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—

The Series A, Series B Shares, Series A* Shares, Series B1 Shares, Series B2 Shares, Series B3 Shares, Series B4 Shares, Series B5 Shares and Series C Shares are collectively referred to as the “preferred shares”. The preferred shares are denominated in US$, which is the functional currency of the issuer, GDS Holdings.

In January 2007, the Company issued 53,625,000 Series A redeemable preferred shares (“Series A Shares”) to a group of investors unrelated to the Company at US$0.3636 (RMB2.8279) per share. Concurrent with the issuance, a holder of bonds payable converted bonds payable of US$3,500 (RMB27,222) into 9,625,000 Series A Shares.

In March 2011, the Company issued 11,550,000 Series B redeemable preferred shares (“Series B Shares”) to a group of investors unrelated to the Company at US$0.7792 (RMB5.1087) per share.

In June 2014, the Company issued 88,352,558 ordinary shares, 14,149,705 Series A* Shares, 33,959,293 Series B1 Shares, 25,618,413 Series B2 Shares, 14,045,432 Series B3 Shares and 23,037,763 Series B4 Shares in connection with the acquisition of EDC Holding (see note 8). Series B1, B2, B3, B4 Shares are collectively referred to as Series B* Shares.

On August 13, 2014, the Company issued 238,526,241 Series C redeemable preferred shares (“Series C Shares”) to an investor unrelated to the Company at US$1.0365 (RMB6.3779) per share, for cash consideration of US$247,238 (RMB1,521,295). The Company incurred issuance costs of US$3,271 (RMB20,128), which were recorded as a reduction in the carrying amount of the redeemable preferred shares.

Prior to the completion of the IPO, the Company concluded that it was probable that the redeemable preferred shares will become redeemable. The Company has elected to recognize changes in the redemption value immediately as they occur and adjust the carrying amount of the redeemable preferred shares to equal the redemption value at the end of each reporting period. Increases in the carrying amount of the redeemable preferred shares are recorded by charges against retained earnings or, in the absence of retained earnings, by charges against paid-in capital. Reductions in the carrying amount of the redeemable preferred shares are recognized only to the extent that increases to the initial carrying amount of the redeemable preferred shares were previously recorded. The resulting increases or decreases in the carrying amount of redeemable preferred shares increases or decreases net loss attributable to ordinary shareholders in the calculation of earnings per share. The increase in redemption value of the redeemable preferred shares was RMB69,116 and RMB110,926 for the years ended December 31, 2014 and 2015, respectively. The decrease in redemption value of the redeemable preferred shares was RMB205,670 for the year ended December 31, 2016 as a result of the preference dividend declared and paid upon the completion of the IPO.

Extinguishment of preferred shares

In connection with the issuance of Series C Shares, on August 13, 2014, the Company repurchased 23,533,064 Series A Shares, 5,503,899 Series A* Shares, 8,413,412 Series B Shares, 13,209,358 Series B1 Shares, 9,964,954 Series B2 Shares, 5,463,340 Series B3 Shares and 8,961,143 Series B4 Shares at US$1.0365 (RMB6.3779) per share, for cash consideration of US$77,790 (RMB478,666), of which RMB455,366 was paid in 2014 and the remaining RMB23,300 was paid in 2015. The Company made the offer for the repurchase to all existing preferred shareholders on that date. The reason for the repurchase of these various series of preferred shares and the ordinary shares was so that the Series C shareholder would hold no less than 40% of the Company’s issued share capital on a fully diluted basis.

In accordance with ASC 260-10-S99, the difference between the cash consideration transferred to the holders of the preferred shares and the carrying amount of the preferred shares (net of issuance costs) is added to net loss to arrive at loss attributable to ordinary shareholders in the calculation of loss per share. The Company recorded the difference of US$12,497 (RMB76,900) between the repurchase price of US$77,790 (RMB478,666) and the carrying amount of such preferred shares of US$65,293 (RMB401,766) against additional paid-in capital, in the absence of retained earnings.

On August 13, 2014 and December 22, 2014, the Company exchanged a total of 35,393,262 preferred shares, comprising of 10,081,891 Series A Shares, 1,729,161 Series A* Shares, 560,105 Series B Shares and 23,022,105 Series B* Shares (collectively, the “Exchanged Shares”) by re-designating those shares into 35,393,262 newly issued Series B5 redeemable preferred shares (“Series B5 Shares”) to facilitate the sale of the Exchanged Shares held by certain selling preferred shareholders. Concurrently, the holders sold the 35,393,262 Series B5 Shares to one investor (B5 Holder), at the purchase price of US$1.0365 (RMB6.3779) per share for a total cash consideration of US$36,685 (RMB225,198). The terms of the B5 Shares were identical to the terms of the Series C Shares.

The exchange, in substance, is the same as a repurchase of the Exchanged Shares from the selling preferred shareholders and a concurrent issuance of Series B5 Shares to the B5 Holder. Accordingly, the Company accounted for the exchange or re-designation of the Exchanged Shares for Series B5 Shares as an extinguishment. The difference of US$4,812 (RMB29,615) between the fair value of the Series B5 Shares of US$36,685 (RMB225,198) and the carrying amount of the Exchanged Shares of US$31,873 (RMB195,583) was recorded against additional paid-in capital, in the absence of retained earnings. In accordance with ASC 260-10-S99, the difference was added to net loss to arrive at loss attributable to ordinary shareholders in the calculation of loss per share.

Modification of preferred shares

In connection with the issuance of Series C Shares on August 13, 2014, the Company and the holders of the remaining Series A, A*, B, B1, B2, B3 and B4 Shares (after the above extinguishment) agreed to modify the terms of their respective preferred shares. The redemption date of these Series A, A*, B, B1, B2, B3 and B4 Shares was extended to the same redemption date as Series C Shares. The holders also agreed to modify the redemption price by reducing the annual rate of return of their respective preferred shares.

The Company determines whether an amendment or modification to the terms of its redeemable convertible preferred shares represents an extinguishment based on a fair value approach. If the fair value of the preferred shares immediately before and after the amendment is significantly different (by more than 10%), the amendment or modification represents an extinguishment. The Company has determined that the amendment to the terms of the preferred shares did not represent an extinguishment, and therefore modification accounting was applied by analogy to the modification guidance contained in ASC 718-20, Compensation—Stock Compensation. Based on a comparison of the fair value of the preferred shares after the amendment to the fair value of the preferred shares immediately before the amendment, the additional fair value change was immaterial. The fair value of the preferred shares before and after the amendment or modification was determined by management with the assistance of a third party valuation firm.

Preference Dividend

On September 29, 2016, the Board of Directors of the Company declared and approved the payment of the preference dividend on the Company’s preferred shares. The entitlement to, and payment of the dividend is conditional on the completion of the Qualified IPO. The amount of the preference dividend to be paid is determined based on the annual rate of 6% from the date of the issuance of the respective preferred shares to the date of the Qualified IPO plus a special rate of return on Series A*, B1, B2 and B4 Shares. The preference dividend is to be paid in either cash or ordinary shares of the Company as elected by each preferred shareholder. The number of ordinary shares to be issued to pay the preference dividends is determined based on the initial public offering price of the Company’s ordinary shares and the dividend amount elected by the preferred shareholder to be paid in ordinary shares. The shareholders of Series A, A*, B, B1, B2 redeemable preferred shares have elected to receive the dividend in cash upon the completion of the Qualified IPO, and the shareholders of Series B4, B5 and C redeemable preferred shares have elected to receive the dividend in ordinary shares of the Company upon the completion of the Qualified IPO.

Upon completion of the IPO on November 7, 2016, the Company paid the preference dividend in an aggregate amount of US$50,812(RMB343,296), of which US$11,449(RMB76,502) was paid in cash and US$39,363(RMB266,794) was paid by issuing an aggregate 31,490,164 ordinary shares to the holders of the preferred shares based on the initial public offering price of US$10.00 per ADS, or US$1.25 per ordinary share.

Terms of the preferred shares

Key terms of the preferred shares are summarized as follows:

Dividends

Holders of the preferred shares are entitled to receive preference dividends at an annual rate of 6% per annum of the respective preferred shares issue price, out of any funds legally available for this purpose, when, as and if declared by the Board of Directors of GDS Holdings. Payment of dividends to certain series of preferred shares is in preference and priority to any declaration or payment of any distribution on other series of preferred shares, details of which are set out in the Company’s Memorandum of Association. The right to receive dividends on the preferred shares shall be cumulative, and the right to such dividends shall accrue to holders of the preferred shares notwithstanding the fact that dividends on said shares are not declared or paid in any calendar year.

Conversion

The holders of preferred shares have the right to convert all or any portion of their holdings into ordinary shares of GDS Holdings at any time. Each preferred share is convertible into one ordinary share, subject to adjustment such as share dividend, share split, consolidation, and recapitalization.

In addition, each preferred share shall (a) automatically be converted into ordinary share at then-effective conversion price immediately prior to the closing of a QIPO, or (b) be converted in to ordinary share at then-effective conversion price with the vote or written consent of the holders of at least 85% of the then outstanding Series A Shares, Series A* Shares, Series B Shares, Series B1 Shares, Series B2 Shares, Series B4 Shares and Series B5 Shares (voting together as a separate class) and the holders of at least 75% of the then outstanding Series C Shares, in each case on an as converted basis.

For the purposes of conversion of preferred shares, QIPO refers to a firm commitment underwritten IPO on an internationally recognized securities exchange (i) with gross cash proceeds to the Company of at least US$100,000, (ii) at an issue price per share being not less than twenty-five percent (25%) above US$1.0365, as adjusted for any recapitalization from time to time, and (iii) resulting in a free float of not less than twenty percent (20%) of the Company’s share capital.

The Company evaluated the embedded conversion option in the convertible preferred shares to determine if the embedded conversion option require bifurcation and accounted for as a derivative. The Company concluded the embedded conversion option did not require it to be bifurcated pursuant to ASC 815. The Company also determined that there was no beneficial conversion feature (“BCF”) attributable to the convertible preferred shares because the initial conversion price was higher than the fair value of the Company’s ordinary shares. The fair value of the Company’s ordinary shares on the commitment date was estimated by management with the assistance of an independent valuation firm. The Company also determined there was no other embedded derivative to be separated from the convertible preferred share.

Upon completion of the IPO on November 7, 2016, 349,087,677 preferred shares were automatically converted into 349,087,677 ordinary shares on a one-to-one basis. Upon conversion, the carrying amounts of the Series A, A*, B, B1, B2, B4, B5 and C redeemable preferred shares have been reclassified as shareholders’ equity under ordinary shares (for the par value) and additional paid-in capital (for the excess of the carrying value of the redeemable preferred shares over the par value).

Voting rights

The holders of the preferred shares have voting rights equivalent to the ordinary shareholders on an “if converted” basis.

Liquidation preference

In the event of any liquidation, dissolution or winding up of the affairs of the Company, whether voluntary or involuntary, the holders of preferred shares shall be entitled to be paid out of the assets of the Company available for distributions a liquidation preference in the amount per preferred share equal to the redemption amount plus all accrued or declared but unpaid dividends.

Payment of liquidation preference on certain series of preferred shares is prior and in preference to any payment on other series of preferred shares, and the liquidation preference in order of priority is Series C, Series B5, Series B*, Series B, Series A*, and Series A, details of which are set out in the Company’s Memorandum of Association.

Redemption

Subject to other redemption requirements set out in the Company’s Memorandum of Association, on or after the 4th anniversary of the original issue date of Series C Shares, the holders of preferred shares may, at the election of the holders of at least 75% of each series of outstanding preferred shares voting together as a separate class on an as converted basis, to the extent permitted by applicable laws, redeem all or any portion of the then outstanding preferred shares at a redemption price equal to the redemption amount, plus an amount equal to all accrued or declared but unpaid dividends thereon, including the 6% cumulative preference dividends whether declared or not.

The redemption amount, shall mean, with respect to the Series A Shares, US$0.363636 per share; with respect to the Series B Shares, US$0.77922 per share, with respect to the Series A* Shares, US$0.1060 per share; with respect to the Series B1 Shares, US$0.5300 per share; with respect to the Series B2 Shares, US$0.5855 per share; with respect to the Series B4 Shares, US$0.4340 per share; with respect to the Series B5 Shares, US$1.036522 per share; and with respect to the Series C Shares, US$1.036522 per share.

FAIR VALUE MEASUREMENT

12 Months Ended

Dec. 31, 2016

FAIR VALUE MEASUREMENT

FAIR VALUE MEASUREMENT

16 FAIR VALUE MEASUREMENT

As of December 31, 2015 and 2016, there was no asset or liability that was measured at fair value on a recurring basis in periods subsequent to their initial recognition.

Following is a description of the valuation techniques that the Company uses to measure fair value of financial assets and financial liabilities:

Short-term financial instruments (restricted cash, accounts receivable and payable, short-term borrowings, and accrued expenses and other payables)—cost approximates fair value because of the short maturity period.

Long-term borrowings—fair value is based on the amount of future cash flows associated with each debt instrument discounted at the Company’s current borrowing rate for similar debt instruments of comparable terms. The carrying values of the long-term borrowings approximate their fair values as all the long-term debt carry variable interest rates which approximate rates currently offered by the Company’s bankers for similar debt instruments of comparable maturities.

Convertible bonds payable—the estimated fair value approximated the carrying value of RMB1,040,550 as of December 31, 2016. The fair value was measured based on the best information available in the circumstances, including expected cash flows and appropriately risk-adjusted discount rates.

ORDINARY SHARES	12 Months Ended
ORDINARY SHARES	Dec. 31, 2016
ORDINARY SHARES
ORDINARY SHARES	17 ORDINARY SHARES Upon incorporation in 2006, the Company issued 110,000,001 ordinary shares with a par value of US$0.00005 (RMB0.000404) each. In June 2014, the Company issued 88,352,558 ordinary shares with a fair value of RMB472,945 to the shareholders of EDC Holding as part of the consideration to acquire EDC Holding (see note 8). In August 2014, the holder of the Bonds due 2015 exchanged principal amount of US$27,860 (RMB171,431) for 38,397,655 ordinary shares (note 11). In connection with the issuance of Series C Shares, on August 13, 2014, the Company repurchased 18,762,292 ordinary shares from certain shareholders at US$1.0365 (RMB6.3779) per share, for a total consideration of US$19,448 (RMB119,664). Upon the repurchase, the Company cancelled such shares. The reason for the repurchase of the various series of preferred shares (note 15) and these ordinary shares was so that the Series C shareholder would hold no less than 40% of the Company’s issued share capital on a fully diluted basis. In August 2016, the Company granted 877,400 fully vested restricted shares to its directors to settle a portion of its remuneration obligation to such directors (note 18). On October 18, 2016, the Board approved the reclassification and redesignation of the Company’s existing preferred shares and ordinary shares into Class A ordinary shares and Class B ordinary shares, whereby immediately prior to the completion of the Company’s initial public offering, (i) all of the Company’s then issued and outstanding preferred shares and ordinary shares were converted into an equal number of Class A ordinary shares, and (ii) all of the Class A ordinary shares then beneficially owned by Mr. William Wei Huang, the founder, chairman and chief executive officer, or entities controlled by him, were converted into an equal number of Class B ordinary shares. All options, regardless of grant date, entitle their holders to receive the equivalent number of Class A ordinary shares once the conditions to vesting and exercise of such share-based compensation awards have been met. Class A ordinary shares and Class B ordinary shares carry equal rights, generally rank pari passu with one another and are entitled to one vote per share at general meetings of shareholders, except for only the following matters at general meetings of shareholders, with respect to which Class B ordinary shares are entitled to 20 votes per share: (i) the election of a simple majority, or six, of our directors; and (ii) any change to our articles of association that would adversely affect the rights of Class B shareholders. With respect to any other matters at general meetings of our shareholders, each Class A ordinary share is entitled to one vote, and each Class B ordinary share is entitled to one vote. For so long as there are Class B ordinary shares outstanding, the holders of Class B ordinary shares will also have the right to nominate one less than a simple majority, or five, of the directors to our board of directors, which directors shall be subject to the voting arrangements described above. Class B ordinary shares are convertible into Class A ordinary shares, and will automatically convert into Class A ordinary shares under certain circumstances. Any Class A ordinary shares which Class B shareholders acquire, including upon the exercise of options, will be converted into Class B ordinary shares. On November 7, 2016 and December 6, 2016, the Company successfully completed its IPO of 19,250,000 ADS (or 154,000,000 Class A ordinary shares) and the underwriters exercised their option to purchase 820,735 additional ADSs (or 6,565,880 Class A ordinary shares), each representing eight of its Class A ordinary shares. Upon completion of the IPO, 349,087,677 preferred shares were automatically converted into 349,087,677 Class A ordinary shares on a one-to-one basis. In addition, an aggregate 31,490,164 Class A ordinary shares were issued to the holders of the preferred shares as a portion of settlement of total preference shares dividend (note 15). Upon completion of the IPO offering and the related transactions described above, the Company’s outstanding share capital consisted of 692,418,707 Class A ordinary shares and 67,590,336 Class B ordinary shares.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(31))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(d))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

+ Details

SHARE-BASED COMPENSATION

12 Months Ended

Dec. 31, 2016

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION

18 SHARE-BASED COMPENSATION

Equity Incentive Plans

The Company adopted the 2014 Equity Incentive Plan (“the 2014 Plan”) in July 2014 for the granting of share options to key employees, directors and external consultants in exchange for their services. The total number of shares, which may be issued under the 2014 Plan, is 29,240,000 shares.

The Company adopted the 2016 Equity Incentive Plan (‘‘the 2016 Plan’’) in August 2016 for the granting of share options, stock appreciation rights and other stock-based award (collectively referred to as the ‘‘Awards’’) to key employees and directors. The maximum aggregate number of shares, which may be subject to Awards under the Plan, is 56,707,560.

Options to directors, officers and employees

In July 2014, the Company granted 12,394,753 share options to employees, officers and directors at an exercise price of US$0.7792 (RMB4.7943) per option. The options have a contractual term of five to six years.

The options vest in accordance with the vesting schedules set out in the respective share option agreements as follows: (1) 63% on the date of grant, 1/48 each month thereafter; (2) 71% on the date of grant, 1/48 each month thereafter; (3) 75% on the date of grant, 1/48 each month thereafter; or (4) 95% on the date of grant, 1/40 each month thereafter.

On May 1, 2016, the Company granted 11,084,840 share options to employees, officers and directors. These share options were fully vested upon the date of grant for past services and have an exercise price of US$0.7792 (RMB 5.0328) per option. The options have a contractual term of five years.

Options to non-employee consultants

In July 2014, the Company granted the following share options to external consultants at an exercise price of US$0.7792 (RMB4.8) per option. The options have a contractual term of five years.

The services performed or to be performed by these external consultants include marketing, technical consultancy, manage telecommunication relationships, strategic, business, operation, and financial planning services.

4,158,315 share options to a group of external consultants. Such options vested immediately on the date of grant for services performed and completed by the consultants.

1,275,000 share options to a consultant. 75% of the options (or 956,250 options) vested immediately on the date of grant for services performed and completed while the remaining 318,750 options vest monthly thereafter in eleven equal monthly instalments for future ongoing services. As of December 31, 2015 and 2016, all options were vested.

400,000 share options to a group of external consultants for further services upon a QIPO. 1/3 of the options vest upon the completion of a QIPO, 1/3 vest upon the 2nd anniversary of a QIPO and 1/3 vest upon the 3rd anniversary of a QIPO. As of December 31, 2015 and 2016, 400,000 and 266,666 forfeitable and unvested non-employee options remained unvested.

In January 2015, the Company granted 1,000,000 share options to an external consultant at an exercise price of US$0.7792 (RMB4.8) per option. The options vest every six months in six equal instalments for future ongoing services. The options have a contractual term of five years. As of December 31, 2015 and 2016, 666,667 and 333,334 forfeitable and unvested non-employee options remained unvested.

These consulting service contracts do not contain a performance commitment. Options to non-employees are forfeitable if not vested. The Company determined that these non-employee options are considered indexed to its own stock and would be equity-classified.

Options that are forfeitable and vest upon the non-employee providing future services are measured at the fair value of the date the performance is completed, which generally coincides with the date on which the options vest and are no longer forfeitable. In accordance with ASC 505-50-S99-1, such options are treated as unissued for accounting purposes until the future services are performed by the non-employees and received by the Company (that is, the options are not considered issued until they vest). During reporting periods prior to completion of performance, the Company measures the cost of the services based on the fair value of the share options at each reporting date using the valuation model applied in previous periods. The portion of the services that the non-employee has rendered is applied to the current measure of fair value to determine the cost to recognize. Changes in the Company’s share price from the grant date to the vesting date result in adjustments to the reported costs of services in each period until performance is completed.

A summary of the option activity is as follows:

	Number of options		Weighted average exercise price	Weighted average grant-date fair value per option
			(RMB)	(RMB)
Options outstanding at January 1, 2014	—		—	—
Granted	17,642,130		4.8	1.9
Forfeited	(178,923	)	4.8	1.9

Options outstanding at December 31, 2014	17,463,207
Granted	519,271		4.8	1.9
Forfeited	(788,944	)	4.8	1.9

Options outstanding at December 31, 2015	17,193,534		4.8	1.9
Granted	11,551,507		5.2	4.9
Forfeited	(155,259	)	4.8	1.9

Options outstanding at December 31, 2016	28,589,782		5.2	3.2


Options vested and expect to vest at December 31, 2016	28,589,782		5.2	3.2

The following table summarizes information with respect to stock options outstanding and stock options exercisable as of December 31, 2016:

	Number of shares	Weighted average remaining contractual life	Weighted average exercise price
		(years)	(RMB)

Options outstanding and exercisable	28,589,782	3.2	5.2

As of December 31, 2015 and 2016, 1,066,667 and 600,000 forfeitable and unvested non-employee options, respectively, were treated as unissued for accounting purposes and were not included in the table above. As of December 31, 2016, there were no unvested employee stock options.

The fair value of the options granted is estimated on the date of grant using the binomial option pricing model with the following assumptions used.

Grant date:	July 2014			January 2015			May 2016
Risk-free rate of return	2.25		%	2.27		%	1.98		%
Volatility	31.40		%	29.80		%	28.50		%
Expected dividend yield	—			—			—
Exercise multiple	2.20			2.20			2.20
Fair value of underlying ordinary share	US$	0.88		US$	0.90		US$	1.51
	RMB	(5.35	)	RMB	(5.5	)	RMB	(9.8	)
Expected term	5-6 years			5 years			5 years

(1)

Volatility

The volatility of the underlying ordinary shares during the lives of the options was estimated based on the historical stock price volatility of comparable listed companies over a period comparable to the expected term of the options.

(2)

Risk-free interest rate

Risk-free interest rate was estimated based on the yield to maturity of China international government bonds with a maturity period close to the expected term of the options.

(3)

Dividend yield

The dividend yield was estimated by the Company based on its expected dividend policy over the expected term of the options.

(4)

Exercise multiple

Exercise multiple represents the value of the underlying share as a multiple of exercise price of the option, which, if achieved, results in exercise of the option.

(5)

Fair value of underlying ordinary shares

The estimated fair value of the ordinary shares underlying the options as of the respective grant dates was determined based on a retrospective valuation with the assistance of a third party appraiser.

Settlement of liability-classified restricted shares award

In May 2016, the Board resolved to pay RMB 11,733 to its directors, of which RMB 4,194 will be settled in cash and RMB7,539 will be settled by issuing of a variable number of the Company’s shares that have an equal value. Accordingly, the Company recorded an expense in general and administrative expenses and a liability of RMB11,733. In August 2016, the Company paid cash of RMB4,194 and issued 877,400 fully vested restricted shares to its directors to fully settle such obligation. Fifty percent (50%) of the restricted shares may not be sold or otherwise disposed of for one year from the grant date. The number of restricted shares required to be issued was determined by the fair value of the restricted shares on the date of settlement and the share-settled portion of the liability of RMB7,539. Upon issuance of the shares to settle the obligation, equity is increased by the amount of the liability settled in shares and no additional share-based compensation expense was recorded.

Restricted shares to directors, officers and employees

In December 2016, the Company granted 12,910,080 non-vested restricted shares to employees, officers and directors. The restricted share awards contained service and market conditions, or service and performance condition, which are tied to the financial performance of the Company. For restricted shares granted, the value of the restricted shares is determined on the fair value of the acquisition date, on which all criteria for establishing the grant dates were satisfied. The value of restricted shares subject to service condition attached is recognized as the compensation expense using the graded-vesting method. The value of restricted shares with performance conditions attached is recognized as compensation expense using the graded-vesting method only when the achievement of performance conditions becomes probable.

A summary of the restricted share activity is as follows:

	Number of Shares		Weighted average grant- date fair value per share (RMB)

Unvested at January 1, 2016	—
Granted	13,787,480		6.1
Vested	(877,400	)	(8.6	)
Forfeited	—		—

Unvested at December 31, 2016	12,910,080		6.0

The Company recognized share-based compensation expenses of RMB 4,697 for the year ended December 31, 2016 related to the restricted share award granted in December 2016. As of December 31, 2016, total unrecognized compensation expense relating to the unvested shares was RMB72,720. The expense is expected to be recognized over a weighted average period of 2.1 years using the graded-vesting attribution method. The Company did not capitalize any of the share-based compensation expenses as part of the cost of any asset for the year ended December 31, 2016.

The fair value of the restricted shares granted is estimated on the date of grant using the Monte Carlo simulation model with the following assumptions used.

Grant date:	December 2016
Risk-free rate of return	0.68~1.65	%
Volatility	22.35~24.80	%
Expected dividend yield	—
Share price at grant date	US$1.24
	(RMB 8.6)
Expected term	1~5 years

(1)

Volatility

Expected volatility is assumed based on the historical volatility of the Company’s comparable companies in the period equal to the expected term of each grant.

(2)

Risk-free interest rate

Risk-free rate equal to the implied yield of zero-coupon United States Government Bond for a term equal to the remaining expected term.

(3)

Dividend yield

The dividend yield was estimated by the Company based on its expected dividend policy over the expected term of the restricted shares.

A summary of share-based compensation expenses for the years ended December 31, 2014, 2015 and 2016 is as follows:

	Year ended December 31,
	2014	2015	2016

Costs of revenue	2,851	484	2,114
Selling and marketing expenses	1,957	325	6,590
General and administrative expenses	22,525	3,252	55,409
Research and development expenses	—	—	52

Total share-based compensation expenses	27,333	4,061	64,165

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

REVENUE

12 Months Ended

Dec. 31, 2016

REVENUE

REVENUE

19 REVENUE

Net revenue consisted of the following:

	Year ended December 31,
	2014	2015	2016

Service revenue	450,940	653,591	1,003,015
Equipment sales	17,397	50,045	52,945

	468,337	703,636	1,055,960

INCOME TAX

12 Months Ended

Dec. 31, 2016

INCOME TAX

INCOME TAX

20 INCOME TAX

Pursuant to the rules and regulations of the Cayman Islands, GDS Holdings is not subject to any income tax in the Cayman Islands.

The Company’s PRC entities are subject to the PRC Corporate Income Tax (“CIT”) rate of 25%.

The Company’s Hong Kong entities are subject to the Hong Kong Profits Tax rate of 16.5%.

The operating results before income tax and the provision for income taxes by tax jurisdictions for the years ended December 31, 2014, 2015 and 2016 are as follows:

	Years ended December 31,
	2014		2015		2016
Loss before income taxes:
PRC	112,572		94,190		144,158
Other jurisdictions	22,010		16,377		140,569

Total loss before income taxes	134,582		110,567		284,727


Current tax expenses:
PRC	436		(1,650	)	311
Other jurisdictions	5		256		1,998

Total current tax expenses(benefits)	441		(1,394	)	2,309


Deferred tax benefits:
PRC	(4,877	)	(10,589	)	(10,935	)
Other jurisdictions	(147	)	—		311

Total deferred tax benefits	(5,024	)	(10,589	)	(10,624	)


Total income taxes benefits	(4,583	)	(11,983	)	(8,315	)

The actual income tax expense reported in the consolidated statements of operations differs from the amount computed by applying the PRC statutory income tax rate to loss before income taxes due to the following:

	Years ended December 31,
	2014		2015		2016

PRC enterprise income tax rate	25.0	%	25.0	%	25.0	%
Non-PRC entities not subject to income tax	(1.8	)%	(3.8	)%	(13.7	)%
Tax differential for entities in non-PRC jurisdiction	(0.8	)%	0.0	%	0.5	%
Tax effect of permanent differences	(0.4	)%	(0.6	)%	(0.3	)%
Change in valuation allowance	(18.4	)%	(9.4	)%	(8.4	)%
Return to provision adjustment	(0.2	)%	(0.4	)%	(0.2	)%

	3.4	%	10.8	%	2.9	%

The components of deferred tax assets and liabilities are as follows:

	As at December 31
	2015		2016
Deferred tax assets:
Bad debt provision	539		—
Government subsidy	4,067		3,763
Accrued expenses	8,732		23,324
Asset retirement obligation	1,444		2,377
Net operating loss carry forwards	135,878		141,749

Total gross deferred tax assets	150,660		171,213
Valuation allowance on deferred tax assets	(118,952	)	(134,935	)

Deferred tax assets, net of valuation allowance	31,708		36,278


Deferred tax liabilities:
Property and equipment	(37,982	)	(36,644	)
Intangible assets	(11,430	)	(22,914	)
Prepaid land use rights	(1,774	)	(1,733	)
Obligation under capital lease and other financing obligations	(10,657	)	(15,641	)

Total deferred tax liabilities	(61,843	)	(76,932	)


Net deferred tax liabilities	(30,135	)	(40,654	)


Analysis as:
Current deferred tax assets (note 4)	5,193		—
Non-current deferred tax assets	2,363		12,626
Non-current deferred tax liabilities	(37,691	)	(53,280	)

Net deferred tax liabilities	(30,135	)	(40,654	)

The following table presents the movement of the valuation allowance for the deferred tax assets:

	Years ended December 31,
	2014		2015	2016

Balance at the beginning of the year	117,065		116,403	118,952
(Decrease) increase during the year	(662	)	2,549	15,983

Balance at the end of the year	116,403		118,952	134,935

Management believes it is more likely than not that the deferred tax asset, net of the valuation allowance as of December 31, 2016, will be realized. However, the amount of the deferred tax assets considered realizable could be reduced in the near term if estimates of future taxable income during the carry forward period are reduced. As of December 31, 2016, the valuation allowance of RMB134,935 was related to the deferred income tax asset of certain subsidiaries of the Company. These entities were in a cumulative loss position, which is a significant negative indicator to overcome that sufficient income will be generated over the periods in which the deferred income tax assets are deductible or utilized. The ultimate realization of deferred income tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible or utilized. Management considers the scheduled reversal of deferred income tax liabilities, projected future taxable income and tax planning strategies in making this assessment.

During the year ended December 31, 2016, certain net operating losses carry forwards expired. A full valuation allowance was provided against these net operating losses carry forwards as of the end of December 31, 2015. The net operating losses carry forwards of the Company’s PRC subsidiaries amounted to RMB493,057 as of December 31, 2016, of which RMB32,405, RMB64,427, RMB222,900, RMB60,137 and RMB113,188 will expire if unused by December 31, 2017, 2018, 2019, 2020 and 2021, respectively.

Uncertainties exist with respect to how the current income tax law in the PRC applies to the Company’s overall operations, and more specifically, with regard to tax residency status. The 2008 EIT Law includes a provision specifying that legal entities organized outside the PRC are considered residents for Chinese income tax purposes if the place of effective management or control is within the PRC. The implementation rules to the New EIT Law provide that non-resident legal entities are considered PRC residents if substantial and overall management and control over the manufacturing and business operations, personnel, accounting, properties, etc., occurs within the PRC. Despite the present uncertainties resulting from the limited PRC tax guidance on the issue, the Company does not believe that the legal entities organized outside the PRC should be treated as residents for 2008 EIT law purposes. If the PRC tax authorities subsequently determine that the Company and its subsidiaries registered outside the PRC are deemed resident enterprises, the Company and its subsidiaries registered outside the PRC will be subject to the PRC income tax at a rate of 25%.

If the Company were to be non-resident for PRC tax purposes, dividends paid to it from profits earned by the PRC subsidiaries after January 1, 2008 would be subject to a withholding tax. The CIT law and its relevant regulations impose a withholding tax at 10%, unless reduced by a tax treaty or agreement, for dividends distributed by a PRC-resident enterprise to its non-PRC-resident corporate investor for earnings generated beginning on January 1, 2008. Undistributed earnings generated prior to January 1, 2008 are exempt from such withholding tax. The Company has not recognized any deferred tax liability for the undistributed earnings of the PRC-resident enterprise as of December 31, 2015 and 2016, as the Company plans to permanently reinvest these earnings in the PRC. Each of the PRC subsidiaries does not have a plan to pay dividends in the foreseeable future and intends to retain any future earnings for use in the operation and expansion of its business in the PRC.

DISTRIBUTION OF PROFIT	12 Months Ended
DISTRIBUTION OF PROFIT	Dec. 31, 2016
DISTRIBUTION OF PROFIT
DISTRIBUTION OF PROFIT	21 DISTRIBUTION OF PROFIT Pursuant to the laws and regulations of the PRC, the Company’s PRC entities are required to allocate at least 10% of their after tax profits, after making good of accumulated losses as reported in their PRC statutory financial statements, to the general reserve fund and have the right to discontinue allocations to the general reserve fund if the balance of such reserve has reached 50% of their registered capital. The general reserves are not available for distribution to the shareholders (except in liquidation) and may not be transferred in the form of loans, advances, or cash dividend. These PRC entities are restricted in their ability to transfer the registered capital and general reserve fund to GDS Holdings in the form of dividends, loans or advances. The restricted portion amounted to RMB1,323,122 and RMB1,975,175 as of December 31, 2015 and 2016, respectively, including non-distributable general reserve fund of nil as of December 31, 2015 and 2016. The parent company financial information of GDS Holdings is disclosed in note 27.

LOSS PER ORDINARY SHARE

12 Months Ended

Dec. 31, 2016

LOSS PER ORDINARY SHARE

LOSS PER ORDINARY SHARE

22 LOSS PER ORDINARY SHARE

The computation of basic and diluted loss per share is as follows:

	Years ended December 31,
	2014		2015		2016
Net loss	129,999		98,584		276,412

Extinguishment of redeemable preferred shares upon repurchase and exchange	106,515		—		—
Change in redemption value of redeemable preferred shares (i)	69,116		110,926		(205,670	)
(Cumulative) Dividend on preferred shares (ii)	3,509		7,127		332,660


Net loss attributable to ordinary shareholders	309,139		216,637		403,402


Weighted average number of ordinary shares outstanding-basic and diluted	162,070,745		217,987,922		299,093,937

Loss per ordinary share - basic and diluted	(1.91	)	(0.99	)	(1.35	)

Note (i): The amount of change in redemption value of redeemable preferred shares for the year ended December 31, 2016 represents the net effect of the accretion to redemption value through the date of automatic conversion into ordinary shares of RMB97,274 and the reduction related to the preference dividends (see Note 15) declared in respect of those redeemable preferred shares of RMB302,944 for which accretion to redemption was previously recorded.

Note (ii): For the years ended December 31, 2014 and 2015, the amounts represent undeclared dividends on redeemable preferred shares that are cumulative and not included in the carrying amount of the redeemable preferred shares. For the year ended December 31, 2016, the amount represented the preference dividend declared and paid of RMB343,296 (see Note 15) upon the IPO less the cumulative dividend on preferred shares amounting to RMB3,509 and RMB7,127 for the years ended December 31, 2014 and 2015.

The following securities were excluded from the computation of diluted loss per share as inclusion would have been anti-dilutive.

	Years ended December 31,
	2014	2015	2016
Share options/restricted shares	17,463,207	17,193,534	41,499,862
Convertible bonds payable	—	59,692,156	93,977,837
Redeemable preferred shares	349,087,677	349,087,677	—

Total	366,550,884	425,973,367	135,477,699

SEGMENT INFORMATION	12 Months Ended
SEGMENT INFORMATION	Dec. 31, 2016
SEGMENT INFORMATION
SEGMENT INFORMATION	23 SEGMENT INFORMATION The Company has one operating segment, which is the design, build-out and operation of data centers. The Company’s chief operating decision maker is the chief executive officer of the Company who reviews the Company’s consolidated results of operations in assessing performance of and making decisions about allocations to this segment. Accordingly, no reportable segment information is presented. Substantially all of the Company’s operations and assets are in the PRC. Consequently, no geographic information is presented.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8981-108599

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e9038-108599

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8971-108599

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8595-108599

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8380-108599

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8933-108599

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8844-108599

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8984-108599

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e9031-108599

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e9054-108599

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8538-108599

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 29
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8864-108599

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8924-108599

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8906-108599

+ Details

MAJOR CUSTOMERS	12 Months Ended
MAJOR CUSTOMERS	Dec. 31, 2016
MAJOR CUSTOMERS
MAJOR CUSTOMERS	24 MAJOR CUSTOMERS During the years ended December 31, 2014 and 2015, the Company had one customer, which generated over 10% of the Company’s total revenues or RMB125,687and RMB141,711, respectively. During the year ended December 31, 2016, the Company had two customers, which generated over 10% of the Company’s total revenues or RMB169,052 and RMB153,863, respectively.

COMMITMENTS

12 Months Ended

Dec. 31, 2016

COMMITMENTS

COMMITMENTS

25 COMMITMENTS

(a) Capital commitments

Capital commitments outstanding at December 31, 2015 and 2016 not provided for in the financial statements were as follows:

	As at December 31, 2015	As at December 31, 2016

Contracted for	272,958	510,999

(b) Lease commitments

The Company’s lease commitments are disclosed in note 13.

RELATED PARTY TRANSACTIONS

12 Months Ended

Dec. 31, 2016

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS

26 RELATED PARTY TRANSACTIONS

In addition to the related party information disclosed elsewhere in the consolidated financial statements, the Company entered into the following material related party transactions.

In 2014, 2015 and 2016, the related parties of the Company are as follows:

Name of party (note i)		Relationship

William Wei Huang (Mr. Huang)		Director and CEO of the Company
STT GDC Pte. Ltd.		Principal preferred shareholder of the Company
Global Data Solutions Ltd.		Principal ordinary shareholder of the Company

SBCVC Holdings Limited (“SBCVC”)		Principal preferred shareholder of the Company

EDC Holding		SBCVC was a common principal preferred shareholder of both GDS Holdings and EDC Holding prior to the acquisition

Notes (i): The English translation of the company names is for reference only. The official names of the companies established in the PRC are in Chinese.

(a)Major transactions with related parties

		Years ended December 31,
		2014	2015	2016

Service fees charged by EDC Holding	26(b)(i)	55,869	—	—


Loans made to EDC Holding	26(b)(i)	307,048	—	—


Interest income	26(b)(i)	4,296	—	—


Repurchase of redeemable preferred shares	26(b)(ii)	273,562	—	—


Preference dividends STT GDC Pte. Ltd	26(b)(iii)	—	—	223,225
SBCVC		—	—	109,665
Other non-principal preferred shareholders		—	—	10,406

		—	—	343,296


Loan from a related party	26(b)(iv)	—	64,936	—


Repayment of a related party loan	26(b)(iv)	—	—	65,474


Convertible bonds from a related party	26(b)(iv)	—	—	327,580


Interest expenses STT GDC Pte. Ltd	26(b)(iv)	—	2,579	32,245
EDC Holding	26(b)(i)	244	—	—

		244	2,579	32,245

(b)Balances with related parties

		As at December 31
	Note	2015	2016
Amount due to:
STT GDC Pte. Ltd.	26(b)(iv)	67,604	—

		67,604	—

(i)Subsequent to the acquisition of EDC Holding by the Company on June 30, 2014, balances and transactions between the Company and EDC Holding are eliminated upon consolidation in the Company’s consolidated financial statements as of and for the years ended December 31, 2014 and 2015. Prior to the acquisition, the Company entered into the following transactions with EDC Holding.

In December 2013, the Company made a prepayment of RMB320,000 to EDC Holding under a service agreement where it was a customer of EDC Holding. The prepayment covered a two-year service period from 2014 to 2015. During the six-month period ended June 30, 2014, EDC Holding provided services to the Company amounting to RMB 55,869.

During the six-month period ended June 30, 2014, the Company provided loans to EDC Holding amounting to RMB307,048. Interest income on the loans amounted to RMB4,296.

In January 2013, EDC Holding provided a loan of US$8,000 (RMB49,222) to the Company. During the six-month period ended June 30, 2014, interest expenses on the loan amounted to RMB 244.

(ii)In August 2014, the Company repurchased 13,905,901 Series A Shares, 4,403,119 Series A* Shares, 1,640,183 Series B Shares, 7,338,532 Series B1 Shares, 6,643,303 Series B2 Shares and 8,961,143 Series B4 Shares from SBCVC at US$1.0365 (RMB 6.3779) per share, for a cash consideration of US$44,458 (RMB273,562). As of December 31, 2014, outstanding consideration payable to SBCVC amounted to RMB 23,300, which was fully settled in 2015.

(iii)Upon completion of the IPO on November 7, 2016, the Company paid the preference dividend in an aggregate amount of US$50,812 (RMB343,296), of which US$11,449 (RMB76,502) was paid in cash and US$39,363 (RMB266,794) was paid by issuing an aggregate 31,490,164 ordinary shares to the holders of the preferred shares based on the initial public offering price of US$10.00 per ADS, or US$1.25 per ordinary share.

(iv)During the year ended December 31, 2015, the Company borrowed a loan of US$10,000 (RMB 64,936) from STT GDC Pte, Ltd., a principal shareholder of the Company. The interest expenses on the loan amounted to US$397(RMB 2,579).

As of December 31, 2015, the amount due to STT GDC Pte. Ltd. comprised US$10,000 (RMB64,936) short-term loan and accrued loan interest of US$397 (RMB2,668).

On January 29, 2016, the Company received the second tranche of US$50,000 (RMB 327,580) from STT GDC Pte. Ltd for subscription of Convertible Bonds due 2019, of which US$10,000 (RMB65,474) was used to settle the outstanding short-term loan of US$10,000 (RMB65,474).

During the year ended December 31, 2016, the related interest expense arising from the Convertible Bonds due 2019 subscribed by STT GDC Pte. Ltd. amounted to RMB32,245.

PARENT ONLY FINANCIAL INFORMATION

12 Months Ended

Dec. 31, 2016

PARENT ONLY FINANCIAL INFORMATION

PARENT ONLY FINANCIAL INFORMATION

27 PARENT ONLY FINANCIAL INFORMATION

The following condensed parent company financial information of GDS Holdings has been prepared using the same accounting policies as set out in the accompanying consolidated financial statements except that the equity method has been used to account for investments in its subsidiaries. As of December 31, 2016, there were no material contingencies, significant provisions of long-term obligations, mandatory dividend or redemption requirements of redeemable stocks or guarantees of GDS Holdings, except for those, which have been separately disclosed in the consolidated financial statements.

Condensed Balance Sheets

	As at December 31
	2015		2016
Assets
Current assets
Cash	643,926		1,030,627
Prepaid expenses	—		1,011

Total current assets	643,926		1,031,638

Investment and loans to subsidiaries	2,152,027		3,054,835
Other non-current assets	—		15,856

Total assets	2,795,953		4,102,329


Liabilities and Shareholders’ Equity (Deficit)

Current liabilities
Accrued expenses and other payables	3,782		23,266
Due to subsidiaries	20,890		927
Due to a related party	67,604		—

Total current liabilities	92,276		24,193

Convertible bonds payable	648,515		1,040,550
Other long-term liabilities	353		51,112

Total liabilities	741,144		1,115,855


Redeemable preferred shares (US$0.00005 par value; 350,563,436 shares authorized; 349,087,677 shares issued and outstanding and aggregate redemption amount of RMB2,277,059 as of December 31, 2015)	2,395,314		—

Shareholders’ equity (deficit)
Ordinary shares (US$0.00005 par value; 675,636,564 and 2,002,000,000 shares authorized; 217,987,922 and 760,009,043 shares issued and outstanding as of December 31, 2015 and 2016, respectively))	76		260
Additional paid-in capital	303,621		4,036,959
Accumulated other comprehensive loss	(61,949	)	(192,080	)
Accumulated deficit	(582,253	)	(858,665	)

Total shareholders’ equity (deficit)	(340,505	)	2,986,474

Commitments and contingencies

Total liabilities, redeemable preferred shares and shareholders’ equity (deficit)	2,795,953		4,102,329

Condensed Statements of Operations

	Years ended December 31,
	2014		2015		2016

Net revenue	—		—		—
Cost of revenue	—		—		(2,381	)

Gross profit	—		—		(2,381	)

Operating expenses
Selling and marketing expenses	(2,387	)	(1,566	)	(8,914	)
General and administrative expenses	(32,166	)	(14,665	)	(82,794	)
Research and development expenses	—		—		(52	)

Loss from operations	(34,553	)	(16,231	)	(94,141	)

Other income (expenses):
Interest income	80		—		16
Interest expenses	(35,192	)	(3,297	)	(97,603	)
Gain on remeasurement of equity investment	62,506		—		—
Equity in loss of subsidiaries	(122,742	)	(79,056	)	(84,952	)
Others, net	(98	)	—		268

Loss before income taxes	(129,999	)	(98,584	)	(276,412	)

Income tax expenses	—		—		—

Net loss	(129,999	)	(98,584	)	(276,412	)

Condensed Statements of Comprehensive Loss

	Years ended December 31,
	2014		2015		2016

Net loss	(129,999	)	(98,584	)	(276,412	)
Other comprehensive income (loss):
Foreign currency translation adjustments, net of nil tax	4,114		(118,491	)	(130,131	)

Comprehensive loss	(125,885	)	(217,075	)	(406,543	)

Condensed Statements of Cash Flows

	Years ended December 31,
	2014		2015		2016

Operating activities:
Net cash used in operating activities	(6,609	)	(4,895	)	(62,591	)


Investing activities
Investment in a subsidiary	(92,300	)	—		—
Deposit paid for a potential acquisition	—		—		(15,000	)
Increase of due from subsidiaries	(925,539	)	(93,101	)	(990,617	)

Net cash used in investing activities	(1,017,839	)	(93,101	)	(1,005,617	)

Financing activities:
Proceeds from issuance of convertible bonds	—		648,950		327,580
Proceeds from issuance of bonds payable	114,950		—		—
Repayment of bonds payable	(4,081	)	(14,330	)	—
Proceeds from a related party loan	—		64,936		—
Repayment of a related party loan	—		—		(65,474	)
Proceeds from issuance of Series C redeemable preferred shares	1,521,295		—		—
Payment of issuance costs of Series C redeemable preferred shares	(20,128	)	—		—
Net proceeds from issuance of ordinary shares for initial public offering	—		—		1,221,518
Payment of preferred shares dividends	—		—		(76,502	)
Repurchase of ordinary shares	(119,664	)	—		—
Repurchase of redeemable preferred shares	(455,366	)	(23,300	)	—

Net cash provided by financing activities	1,037,006		676,256		1,407,122
Effect of exchange rate changes on cash	(4,459	)	57,565		47,787


Net increase in cash	8,099		635,825		386,701
Cash at beginning of year	2		8,101		643,926

Cash at end of year	8,101		643,926		1,030,627


Supplemental disclosures of cash flow information
Interest paid	1,317		3,463		45,495

Supplemental disclosures of non-cash investing and financing activities
Issuance of ordinary shares to settle preference dividend	—		—		266,794
Issuance of ordinary shares in exchange of bonds payable	205,536		—		—
Issuance of ordinary and preferred shares for the acquisition of EDC Holding	1,184,242		—		—

- Definition

The entire disclosure for condensed financial information, including the financial position, cash flows, and the results of operations of the registrant (parent company) as of the same dates or for the same periods for which audited consolidated financial statements are being presented. Alternatively, the details of this disclosure can be reported by the specific parent company taxonomy elements, indicating the appropriate date and period contexts in an instance document.

+ References + Details

SUBSEQUENT EVENTS	12 Months Ended
SUBSEQUENT EVENTS	Dec. 31, 2016
SUBSEQUENT EVENTS
SUBSEQUENT EVENTS	28 SUBSEQUENT EVENTS (a)Acquisition of Shenzhen 5 On March 16, 2017, the Company, through GDS Beijing, entered into an equity purchase agreement to acquire all of the equity interests in a target group from a third party for an aggregate purchase price of RMB313,000 (including contingent considerations of RMB312,000). The target group owns a data center project in Shenzhen, China (Shenzhen 5). Management does not believe this acquisition is significant as measured by the assets or pre-tax earnings (loss) of the acquiree as a percentage of the Company’s consolidated assets or pre-tax earnings (loss), respectively. (b)Contract termination On November 12, 2016, the Company received a written notice from its end customer to early terminate a colocation service agreement, with effect from January 2017. On March 15, 2017, the Company received a contract termination fee of US$6,742 (RMB46,769). (c)New Loan Facilities On March 30, 2017, two subsidiaries of the Company entered into a facility agreement with third party banks for a total amount of US$45,000 (RMB310,700). The loans are required to be repaid in full prior to the maturity date upon the occurrence of any of the Early Repayment Events. In addition, the loan facilities contain financial covenants that limit certain financial ratios during the relevant period, as defined in the facilities. On April 10, 2017, the Company fully drew down the loans under such facilities of US$45,000 (RMB310,700). The loans bear an effective interest rate of 5.41% per annum and mature on October 10, 2018.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

12 Months Ended

Dec. 31, 2016

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Principles of Consolidation

(a) Principles of Consolidation

The following is a summary of the contractual VIE Agreements entered among GDS Management Company, the VIEs, and the shareholders of the VIEs.

Levy fines on the Company or confiscate income of the Company;

Revoke or suspend the VIEs’ business or operating licenses;

Discontinue or place restrictions or onerous conditions on VIE’s operations;

Require the Company to discontinue their operations in the PRC;

Require the Company to undergo a costly and disruptive restructuring;

Take other regulatory or enforcement actions that could be harmful to the Company’s business.

	Years ended December 31,
	2014		2015		2016
Net revenue	9,244		30,598		846,168
Net (loss) income	(4,799	)	(5,327	)	22,246
Net cash (used in) provided by operating activities	(1,034	)	8,631		239,624
Net cash used in investing activities	(20	)	(1,456	)	(158,681	)
Net cash provided by financing activities	—		—		304,973

Use of estimates

(b) Use of estimates

Cash and cash equivalents

Restricted cash

(d) Restricted cash

Fair value of financial instruments

(e) Fair value of financial instruments

Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date.

Accounts receivable

(f) Accounts receivable

Property and equipment

(g) Property and equipment

The estimated useful lives are presented below.

Buildings		20 - 30 years
Data center equipment
- Machinery		10 - 20 years
- Other equipment		3 - 5 years
Leasehold improvement		Shorter of the lease term and the
		estimated useful lives of the assets
Furniture and office equipment		3 - 5 years
Vehicles		5 years

Long-lived assets held for sale

(h) Long-lived assets held for sale

Leases

(i) Leases

As of December 31, 2015 and 2016, assets under capital leases and other financing obligations represent data center buildings and data center equipment.

Asset retirement costs

(j) Asset retirement costs

Asset retirement obligations are recorded in other long-term liabilities. The following table summarizes the activity of the asset retirement obligation liability:

Asset retirement obligations as of January 1, 2014		—
Additions		2,148
Accretion expense		73


Asset retirement obligations as of December 31, 2014		2,221
Additions		3,299
Accretion expense		255


Asset retirement obligations as of December 31, 2015		5,775
Additions		2,942
Accretion expense		588


Asset retirement obligations as of December 31, 2016		9,305

Intangible assets

(k) Intangible assets

Intangible assets acquired in the acquisition comprised of customer relationships and favorable leases.

The weighted-average amortization period by major intangible asset class is as follows:

Customer relationships	5-8 years
Favorable lease	20 years

Prepaid land use rights

(l) Prepaid land use rights

Goodwill

(m) Goodwill

Goodwill is an asset representing the future economic benefits arising from other assets acquired in the acquisition that are not individually identified and separately recognized.

Impairment of long-lived assets

(n) Impairment of long-lived assets

Value-added-tax ("VAT")

(o) Value-added-tax (“VAT”)

Derivative financial instruments

(p) Derivative financial instruments

Commitment and contingencies

(q) Commitment and contingencies

Revenue recognition

(r) Revenue recognition

These criteria as they relate to each of the following major revenue generating activities are described below.

Cash received in advance from customers prior to the delivery of the colocation or managed hosting and cloud services is recorded as deferred revenue.

The sale of IT equipment is recognized when delivery has occurred and the customer accepts the equipment and the Company has no performance obligation after the delivery.

Sales taxes collected from customers and remitted to governmental authorities are excluded from revenues in the consolidated statements of operations.

Cost of revenues

(s) Cost of revenues

Cost of revenues consists primarily of utility costs, depreciation of property and equipment, rental costs, labor costs and other costs directly attributable to the provision of the service revenue.

Research and development and advertising costs

(t) Research and development and advertising costs

Advertising costs amounted to RMB2,363, RMB4,128 and RMB8,942 in 2014, 2015 and 2016, respectively.

Start-up costs

(u) Start-up costs

Government grants

(v) Government grants

As of December 31, 2015 and 2016, deferred government grants of RMB16,268 and RMB14,051 are recorded in other long-term liabilities in the consolidated balance sheets.

Capitalized interest

(w) Capitalized interest

A reconciliation of total interest costs to ‘‘Interest expenses’’ as reported in the consolidated statements of operations for 2014, 2015 and 2016 is as follows:

	Years ended December 31,
	2014		2015		2016

Total interest costs	136,458		138,260		324,085
Less: interest costs capitalized	(4,550	)	(11,359	)	(58,851	)

Interest expenses	131,908		126,901		265,234

Debt issuance costs

(x) Debt issuance costs

Debt issuance costs are capitalized and are amortized over the life of the related loans based on the effective interest method. Such amortization is included as a component of interest expense.

Income tax

(y) Income tax

Share-based compensation

(z) Share-based compensation

For further information on stock-based compensation, see Note 18 below.

Employee benefits

(aa) Employee benefits

Foreign currency translation and foreign currency risks

(bb) Foreign currency translation and foreign currency risks

The functional currency of GDS Holdings is the USD, whereas the functional currency of its PRC subsidiaries and consolidated VIEs is the RMB.

Translation adjustments are reported in other comprehensive income and accumulated in the translation adjustment component of equity until the sale or liquidation of the foreign entity.

	RMB	USD	HKD	JPY	EUR
In PRC	491,631	32,783	—	—	—
In Hong Kong	9,494	153,307	12,546	6,592	96
In Cayman Island	—	4,993	—	—	—

Total in original currency	501,125	191,083	12,546	6,592	96

RMB equivalent	501,125	1,325,547	11,222	394	704

Concentration of credit risk

(cc) Concentration of credit risk

Earnings (loss) per share

(dd) Earnings (loss) per share

Recently Adopted and Issued Accounting Standards

(ee) Recently Adopted Accounting Standards

(ff) Recently Issued Accounting Standards

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2016

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Schedule of net revenue and net income (loss), operating, investing and financing cash flows of VIEs

	Years ended December 31,
	2014		2015		2016
Net revenue	9,244		30,598		846,168
Net (loss) income	(4,799	)	(5,327	)	22,246
Net cash (used in) provided by operating activities	(1,034	)	8,631		239,624
Net cash used in investing activities	(20	)	(1,456	)	(158,681	)
Net cash provided by financing activities	—		—		304,973

Schedule of estimated useful lives of property and equipment

Buildings		20 - 30 years
Data center equipment
- Machinery		10 - 20 years
- Other equipment		3 - 5 years
Leasehold improvement		Shorter of the lease term and the
		estimated useful lives of the assets
Furniture and office equipment		3 - 5 years
Vehicles		5 years

Schedule of asset retirement obligations

Asset retirement obligations as of January 1, 2014		—
Additions		2,148
Accretion expense		73


Asset retirement obligations as of December 31, 2014		2,221
Additions		3,299
Accretion expense		255


Asset retirement obligations as of December 31, 2015		5,775
Additions		2,942
Accretion expense		588


Asset retirement obligations as of December 31, 2016		9,305

Schedule of weighted-average amortization period of acquired intangible assets

Customer relationships	5-8 years
Favorable lease	20 years

Schedule of reconciliation of total interest costs to interest expenses

	Years ended December 31,
	2014		2015		2016

Total interest costs	136,458		138,260		324,085
Less: interest costs capitalized	(4,550	)	(11,359	)	(58,851	)

Interest expenses	131,908		126,901		265,234

Schedule of cash and restricted cash deposited in major financial institutions located in PRC, Hong Kong, and Cayman Island financial institutions

	RMB	USD	HKD	JPY	EUR
In PRC	491,631	32,783	—	—	—
In Hong Kong	9,494	153,307	12,546	6,592	96
In Cayman Island	—	4,993	—	—	—

Total in original currency	501,125	191,083	12,546	6,592	96

RMB equivalent	501,125	1,325,547	11,222	394	704

- Definition

Tabular disclosure of the significant judgments and assumptions made in determining whether a variable interest (as defined) held by the entity requires the variable interest entity (VIE) (as defined) to be consolidated and (or) disclose information about its involvement with the VIE, individually or in aggregate (as applicable); the nature of restrictions, if any, on the consolidated VIE's assets and on the settlement of its liabilities reported by an entity in its statement of financial position, including the carrying amounts of such assets and liabilities; the nature of, and changes in, the risks associated with involvement in the VIE; how involvement with the VIE affects the entity's financial position, financial performance, and cash flows; the lack of recourse if creditors (or beneficial interest holders) of the consolidated VIE have no recourse to the general credit of the primary beneficiary (if applicable); the terms of arrangements, giving consideration to both explicit arrangements and implicit variable interests, if any, that could require the entity to provide financial support to the VIE, including events or circumstances that could expose the entity to a loss; the methodology used by the entity for determining whether or not it is the primary beneficiary of the variable interest entity; the significant factors considered and judgments made in determining that the power to direct the activities of a VIE that most significantly impact the VIE's economic performance are shared (as defined); the carrying amounts and classification of assets and liabilities of the VIE included in the statement of financial position; the entity's maximum exposure to loss, if any, as a result of its involvement with the VIE, including how the maximum exposure is determined and significant sources of the entity's exposure to the VIE; a comparison of the carrying amounts of the assets and liabilities and the entity's maximum exposure to loss; information about any liquidity arrangements, guarantees, and (or) other commitments by third parties that may affect the fair value or risk of the entity's variable interest in the VIE; whether or not the entity has provided financial support or other support (explicitly or implicitly) to the VIE that it was not previously contractually required to provide or whether the entity intends to provide that support, including the type and amount of the support and the primary reasons for providing the support; and supplemental information the entity determines necessary to provide.

+ References + Details

ACCOUNTS RECEIVABLES, NET (Tables)

12 Months Ended

Dec. 31, 2016

ACCOUNTS RECEIVABLES, NET

Schedule of accounts receivables, net

	As at December 31
	2015		2016

Accounts receivables	113,169		198,851
Less: allowance for doubtful accounts	(2,156	)	—


Accounts receivables, net	111,013		198,851

Schedule of allowance for doubtful accounts

	Year ended December 31,
	2014	2015	2016

Balance at the beginning of the year	—	2,156	2,156
Allowance made during the year	2,156	—	—
Reversal during the year	—	—	(2,156	)

Balance at the end of the year	2,156	2,156	—

OTHER CURRENT ASSETS (Tables)

12 Months Ended

Dec. 31, 2016

OTHER CURRENT ASSETS

Schedule of Other current assets

	As at December 31
	2015	2016

Rental and other deposits	9,456	30,136
Deferred tax assets, current (note 20)	5,193	—
Assets held for sale	18,531	18,531
Others	508	484

	33,688	49,151

PROPERTY AND EQUIPMENT, NET (Tables)

12 Months Ended

Dec. 31, 2016

PROPERTY AND EQUIPMENT, NET

Schedule of property and equipment

	As at December 31, 2015		As at December 31, 2016

At cost:
Buildings	1,049,376		1,652,641
Data center equipment	891,089		1,349,069
Leasehold improvement	554,450		1,202,979
Furniture and office equipment	32,001		31,270
Vehicles	2,728		3,199


	2,529,644		4,239,158
Less: Accumulated depreciation	(421,475	)	(613,658	)


	2,108,169		3,625,500
Construction in progress	404,518		697,391


Property and equipment, net	2,512,687		4,322,891

Schedule of capital leases assets

	As at December 31, 2015		As at December 31, 2016

At cost:
Buildings(note)	627,874		1,286,079
Data center equipment	12,718		26,375

	640,592		1,312,454
Less: Accumulated depreciation	(32,061	)	(64,151	)

	608,531		1,248,303

Schedule of depreciation of property and equipment

	Year ended December 31,
	2014	2015	2016

Cost of revenue	71,024	131,097	206,724
General and administrative expenses	6,922	4,767	5,425
Research and development expenses	—	—	724


	77,946	135,864	212,873

INTANGIBLE ASSETS, NET (Tables)

12 Months Ended

Dec. 31, 2016

INTANGIBLE ASSETS, NET

Schedule of Intangible assets

	Note	As at December 31, 2015		As at December 31, 2016

Customer relationships	8	44,822		104,322
Favorable lease	8	15,500		15,500

		60,322		119,822
Less: accumulated amortization		(13,387	)	(27,253	)

Intangible assets, net		46,935		92,569

Schedule of Estimated future amortization expense

Fiscal year ending December 31,
2017		16,939
2018		16,939
2019		16,939
2020		8,789
2021		8,789
Thereafter		24,174

Total		92,569

PREPAID LAND USE RIGHTS (Tables)

12 Months Ended

Dec. 31, 2016

PREPAID LAND USE RIGHTS

Schedule of prepaid land use rights

	As at December 31
	2015		2016

Prepaid land use rights	28,370		28,370
Less: Accumulated amortization	(962	)	(1,578	)

Prepaid land use rights, net	27,408		26,792

BUSINESS COMBINATION (Tables)

12 Months Ended

Dec. 31, 2016

BUSINESS COMBINATION

Schedule of movement of goodwill

	As at December 31
	2015	2016

Balance at the beginning of the year	1,294,664	1,294,664
Addition during the year	—	46,423

Balance at end of year	1,294,664	1,341,087

Schedule of fair value of consideration transferred

Fair value of ordinary shares issued		472,945
Fair value of redeemable preferred shares issued		711,297

Total fair value of total consideration transferred		1,184,242

EDC Holding

BUSINESS COMBINATION

Schedule of the identifiable assets acquired and liabilities assumed in the business combination

	Note
Fair value of consideration transferred		1,184,242
Fair value of non-controlling equity interest previously held by the Company	(i)	62,506

Sub-total		1,246,748

Effective settlement of pre-existing relationships	(ii)	549,521

Recognized amounts of identifiable assets acquired and liabilities assumed
Cash		(40,999	)
Property and equipment	(iii)	(1,535,246	)
Identifiable intangible assets	(iv)	(60,322	)
Other assets		(96,508	)
Short-term borrowings and current portion of long-term borrowings		178,638
Accounts payable		290,326
Obligations under capital leases, current		35,234
Long-term borrowings, excluding current portion		342,130
Deferred tax liabilities		45,748
Obligations under capital leases, non-current		250,318
Other liabilities		89,076

Total identifiable net assets		(501,605	)

Goodwill		1,294,664

Note (i): The gain of RMB62,506 arising from the re-measurement of the existing carrying value of investment in EDC Holding to fair value was recognized in the consolidated statement of operations. The fair value of the previous held non-controlling equity interest was determined by management with the assistance of a third party appraiser.

Note (ii): Prior to the business combination, the Company had the following pre-existing relationships with EDC Holding: (1) a prepayment due from EDC Holding of RMB254,633 for future services under a service contract with EDC Holding; (2) outstanding loans of RMB344,110 due from EDC Holding; and (3) a loan of US$8,000 (RMB49,222) issued from EDC Holding to the Company in January 2013. No gain or loss was recognized from the effective settlement of such pre-existing relationship between the Company and EDC Holding. At the acquisition date, the amount due from EDC Holding of RMB598,743 and the amount due to EDC Holding of RMB49,222 are eliminated upon consolidation.

Note (iii): Property and equipment acquired included data center buildings of RMB624,090, properties acquired under capital lease of RMB422,874, data center equipment of RMB299,801, leasehold improvement of RMB2,694, furniture and office equipment of RMB958, vehicles of RMB749 and construction in progress of RMB184,080.

Note (iv): Identifiable intangible assets acquired consisted of customer relationships of RMB44,822 with an estimated useful life of 5 to 6 years and favorable lease of RMB15,500 with estimated useful life of 20 years.

WTENG

BUSINESS COMBINATION

Schedule of the identifiable assets acquired and liabilities assumed in the business combination

	Note
Fair value of consideration		129,500
Effective settlement of pre-existing relationships upon consolidation	(i)	43,161
Recognized amounts of identifiable assets acquired and liabilities assumed
Cash		(1,237	)
Property and equipment	(ii)	(281,437	)
Identifiable intangible assets	(iii)	(59,500	)
Other assets		(25,363	)
Accounts payable		131,114
Capital lease and other financing obligations, current		12,097
Capital lease and other financing obligations, non-current		68,584
Deferred tax liabilities		21,143
Other liabilities		8,361

Total identifiable net assets		(126,238	)

Goodwill	(iv)	46,423

Note (i): Prior to the acquisition of WTENG, in February and May 2016, the Company lent short-term loans of RMB40,000 and RMB2,000, respectively, to WTENG. The loans bear an interest rate of 10% per annum and mature in September 2016. No gain or loss was recognized from the effective settlement of such pre-existing relationship between the Company and WTENG. At the acquisition date, the amount due from WTENG of RMB 43,161, including loan principal of RMB42,000 and interest receivable of RMB1,161, is eliminated upon consolidation.

Note (ii): Property and equipment acquired included properties and equipment acquired under capital lease and other financing arrangement of RMB102,785, data center equipment of RMB19,895, leasehold improvement of RMB132,462 and construction in progress of RMB26,295.

Note (iii): Identifiable intangible assets acquired consisted of customer relationships of RMB59,500 with an estimated useful life of 7 to 8 years.

Note (iv): Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in the acquisition of WTENG. Goodwill is assigned to the design, build-out and operation of data centers reporting unit. Goodwill primarily represents the expected synergies from combining operations of WTENG with those of the Company and intangible assets that do not qualify for separate recognition and is not deductible for tax purposes. In accordance with ASC350, goodwill is not amortized but is tested for impairment.

OTHER NON-CURRENT ASSETS (Tables)

12 Months Ended

Dec. 31, 2016

OTHER NON-CURRENT ASSETS

Schedule of other non-current assets

	As at December 31
	2015	2016

Deposits for leases	46,423	62,985
Other deposits	—	15,000
Others	11,093	20,740

	57,516	98,725

LOANS AND BORROWINGS (Tables)

12 Months Ended

Dec. 31, 2016

LOANS AND BORROWINGS

Schedule of borrowings

	As at December 31, 2015	As at December 31, 2016

Short-term borrowings	333,000	239,777
Current portion of long-term borrowings	95,218	388,701

Sub-total	428,218	628,478
Long-term borrowings, excluding current portion	958,264	1,509,676

Total loans and borrowings	1,386,482	2,138,154

Schedule of short-term borrowings

	As at December 31, 2015	As at December 31, 2016

Unsecured short-term loans and borrowings	60,000	—
Secured short-term loans and borrowings	273,000	239,777

	333,000	239,777

Schedule of assets to secure the short-term borrowings

	As at December 31, 2015	As at December 31, 2016

Accounts receivable	20,221	19,914
Property and equipment, net	144,540	—
Prepaid land use rights, net	14,602	—

	179,363	19,914

Schedule of long-term borrowings

	As at December 31, 2015	As at December 31, 2016

Unsecured long-term loans and borrowings	2,844	—
Secured long-term loans and borrowings	1,050,638	1,898,377



	1,053,482	1,898,377

Schedule of assets to secure the long-term borrowings

	As at December 31, 2015	As at December 31, 2016

Accounts receivable	22,290	67,433
Property and equipment, net	434,984	512,566
Prepaid land use rights, net	6,381	20,735

	463,655	600,734

Schedule of aggregate maturities of the long-term loans and borrowings

		Long-term borrowings
Twelve-months ending December 31 ,
2017		388,701
2018		324,473
2019		385,388
2020		359,179
2021		412,457
Thereafter		28,179


		1,898,377

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

+ Details

ACCRUED EXPENSES AND OTHER PAYABLES (Tables)

12 Months Ended

Dec. 31, 2016

ACCRUED EXPENSES AND OTHER PAYABLES

Summary of Accrued expenses and other payables

	As at December 31
	2015	2016

Accrued rental expenses	12,951	12,744
Accrued utility expenses	8,548	14,348
Accrued payroll and welfare benefits	27,062	31,165
Accrued interest expenses	23,722	67,324
Accrued professional service fees	8,352	11,867
Other taxes payables	14,296	11,470
Income tax payable (note 20)	8,955	15,265
Consideration payable for the acquisition of WTENG (note 8)	—	25,900
Other payables	14,430	17,867

	118,316	207,950

LEASE (Tables)

12 Months Ended

Dec. 31, 2016

LEASE

Schedule of capital lease and other financing obligations

	December 31, 2015					December 31, 2016
	Capital lease obligations		Other financing obligations	Total		Capital lease obligations		Other financing obligations		Total
Within 1 year	51,591		—	51,591		71,300		22,044		93,344
After 1 year but within 2 years	60,019		—	60,019		85,783		38,443		124,226
After 2 years but within 3 years	64,938		—	64,938		92,677		39,548		132,225
After 3 years but within 4 years	69,089		—	69,089		193,202		41,586		234,788
After 4 years but within 5 years	172,079		—	172,079		71,501		42,287		113,788
After 5 years	395,251		—	395,251		716,089		725,178		1,441,267


Total	812,967		—	812,967		1,230,552		909,086		2,139,638

Less total future interest	(339,283	)	—	(339,283	)	(552,060	)	(450,670	)	(1,002,730	)
Less: estimated building costs	—		—	—		—		(25,356	)	(25,356	)


Present value of lease and other financing obligations	473,684		—	473,684		678,492		433,060		1,111,552

Including:
Current portion				48,745						88,593

Non-current portion				424,939						1,022,959

Schedule of Future minimum operating lease payments

Future minimum operating lease payments as of December 31, 2016 are summarized as follow:

Twelve-months ending December 31,
2017		124,293
2018		98,566
2019		75,657
2020		57,268
2021		36,822
Thereafter		445,607

Total		838,213

Other long-term liabilities (Tables)

12 Months Ended

Dec. 31, 2016

Other long-term liabilities

Schedule of other long-term liabilities

	As at December 31, 2015	As at December 31, 2016

Payables for purchase of property and equipment	31,152	37,126
Accrued interests	25,810	51,112
Deferred government grants	16,268	14,051
Others	5,775	9,417

Total	79,005	111,706

REDEEMABLE PREFERRED SHARES (Tables)

12 Months Ended

Dec. 31, 2016

REDEEMABLE PREFERRED SHARES

Schedule of movement of the redeemable preferred shares

	Series A				Series A*				Series B				Series B1				Series B2				Series B3				Series B4				Series B5				Series C				Total
	Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000		Shares		RMB’000
Balance at January 1, 2014	63,250,000		198,434		—		—		11,550,000		64,056		—		—		—		—		—		—		—		—		—		—		—		—		74,800,000		262,490
Issuance of redeemable preferred shares
—in relation to business combination	—		—		14,149,705		80,965		—		—		33,959,293		236,108		25,618,413		165,506		14,045,432		85,554		23,037,763		143,164		—		—		—		—		110,810,606		711,297
—third party investor	—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		238,526,241		1,501,167		238,526,241		1,501,167
Extinguishment of redeemable preferred shares upon repurchase	(23,533,064	)	(76,473	)	(5,503,899	)	(31,497	)	(8,413,412	)	(48,593	)	(13,209,358	)	(91,847	)	(9,964,954	)	(64,383	)	(5,463,340	)	(33,281	)	(8,961,143	)	(55,692	)	—		—		—		—		(75,049,170	)	(401,766	)
Extinguishment of redeemable preferred shares upon exchange	(10,081,891	)	(32,803	)	(1,729,161	)	(9,896	)	(560,105	)	(3,276	)	(9,222,193	)	(63,800	)	(5,217,820	)	(33,540	)	(8,582,092	)	(52,268	)	—		—		35,393,262		225,198		—		—		—		29,615
Changes in redemption value	—		6,824		—		—		—		2,393		—		—		—		—		—		—		—		—		—		5,210		—		54,689		—		69,116
Foreign exchange impact	—		1,292		—		3		—		500		—		(313	)	—		(164	)	—		(5	)	—		5		—		(725	)	—		(8,473	)	—		(7,880	)

Balance at December 31, 2014 and January 1, 2015	29,635,045		97,274		6,916,645		39,575		2,576,483		15,080		11,527,742		80,148		10,435,639		67,419		—		—		14,076,620		87,477		35,393,262		229,683		238,526,241		1,547,383		349,087,677		2,164,039
Changes in redemption value	—		4,029		—		—		—		754		—		—		—		—		—		—		—		—		—		13,715		—		92,428		—		110,926
Foreign exchange impact	—		6,125		—		—		—		955		—		—		—		—		—		—		—		—		—		14,640		—		98,629		—		120,349

Balance at December 31, 2015 and January 1, 2016	29,635,045		107,428		6,916,645		39,575		2,576,483		16,789		11,527,742		80,148		10,435,639		67,419		—		—		14,076,620		87,477		35,393,262		258,038		238,526,241		1,738,440		349,087,677		2,395,314
Changes in redemption value	—		(39,098	)	—		—		—		(3,921	)	—		—		—		—		—		—		—		—		—		(21,016	)	—		(141,635	)	—		(205,670	)
Conversion to ordinary shares	(29,635,045	)	(72,965	)	(6,916,645	)	(43,564	)	(2,576,483	)	(13,600	)	(11,527,742	)	(88,221	)	(10,435,639	)	(74,209	)	—		—		(14,076,620	)	(96,287	)	(35,393,262	)	(248,455	)	(238,526,241	)	(1,673,831	)	(349,087,677	)	(2,311,132	)
Foreign exchange impact	—		4,635		—		3,989		—		732		—		8,073		—		6,790		—		—		—		8,810		—		11,433		—		77,026		—		121,488

Balance at December 31, 2016	—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—

SHARE-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2016

SHARE-BASED COMPENSATION

Summary of the share option activities

	Number of options		Weighted average exercise price	Weighted average grant-date fair value per option
			(RMB)	(RMB)
Options outstanding at January 1, 2014	—		—	—
Granted	17,642,130		4.8	1.9
Forfeited	(178,923	)	4.8	1.9

Options outstanding at December 31, 2014	17,463,207
Granted	519,271		4.8	1.9
Forfeited	(788,944	)	4.8	1.9

Options outstanding at December 31, 2015	17,193,534		4.8	1.9
Granted	11,551,507		5.2	4.9
Forfeited	(155,259	)	4.8	1.9

Options outstanding at December 31, 2016	28,589,782		5.2	3.2


Options vested and expect to vest at December 31, 2016	28,589,782		5.2	3.2

Summary of information with respect to stock options outstanding and stock options exercisable

The following table summarizes information with respect to stock options outstanding and stock options exercisable as of December 31, 2016:

	Number of shares	Weighted average remaining contractual life	Weighted average exercise price
		(years)	(RMB)

Options outstanding and exercisable	28,589,782	3.2	5.2

Assumptions used to estimate fair value of stock options

Grant date:	July 2014			January 2015			May 2016
Risk-free rate of return	2.25		%	2.27		%	1.98		%
Volatility	31.40		%	29.80		%	28.50		%
Expected dividend yield	—			—			—
Exercise multiple	2.20			2.20			2.20
Fair value of underlying ordinary share	US$	0.88		US$	0.90		US$	1.51
	RMB	(5.35	)	RMB	(5.5	)	RMB	(9.8	)
Expected term	5-6 years			5 years			5 years

Summary of the restricted share activity

	Number of Shares		Weighted average grant- date fair value per share (RMB)

Unvested at January 1, 2016	—
Granted	13,787,480		6.1
Vested	(877,400	)	(8.6	)
Forfeited	—		—

Unvested at December 31, 2016	12,910,080		6.0

Summary of share-based compensation expenses

	Year ended December 31,
	2014	2015	2016

Costs of revenue	2,851	484	2,114
Selling and marketing expenses	1,957	325	6,590
General and administrative expenses	22,525	3,252	55,409
Research and development expenses	—	—	52

Total share-based compensation expenses	27,333	4,061	64,165

Restricted shares

SHARE-BASED COMPENSATION

Assumptions used to estimate fair value of the restricted shares

Grant date:	December 2016
Risk-free rate of return	0.68~1.65	%
Volatility	22.35~24.80	%
Expected dividend yield	—
Share price at grant date	US$1.24
	(RMB 8.6)
Expected term	1~5 years

REVENUE (Tables)

12 Months Ended

Dec. 31, 2016

REVENUE

Schedule of Net revenue

	Year ended December 31,
	2014	2015	2016

Service revenue	450,940	653,591	1,003,015
Equipment sales	17,397	50,045	52,945

	468,337	703,636	1,055,960

INCOME TAX (Tables)

12 Months Ended

Dec. 31, 2016

INCOME TAX

Schedule of operating results before income tax and the provision for income taxes by tax jurisdictions

	Years ended December 31,
	2014		2015		2016
Loss before income taxes:
PRC	112,572		94,190		144,158
Other jurisdictions	22,010		16,377		140,569

Total loss before income taxes	134,582		110,567		284,727


Current tax expenses:
PRC	436		(1,650	)	311
Other jurisdictions	5		256		1,998

Total current tax expenses(benefits)	441		(1,394	)	2,309


Deferred tax benefits:
PRC	(4,877	)	(10,589	)	(10,935	)
Other jurisdictions	(147	)	—		311

Total deferred tax benefits	(5,024	)	(10,589	)	(10,624	)


Total income taxes benefits	(4,583	)	(11,983	)	(8,315	)

Schedule of reconciliation of differences between PRC statutory tax rate and effective tax rate

	Years ended December 31,
	2014		2015		2016

PRC enterprise income tax rate	25.0	%	25.0	%	25.0	%
Non-PRC entities not subject to income tax	(1.8	)%	(3.8	)%	(13.7	)%
Tax differential for entities in non-PRC jurisdiction	(0.8	)%	0.0	%	0.5	%
Tax effect of permanent differences	(0.4	)%	(0.6	)%	(0.3	)%
Change in valuation allowance	(18.4	)%	(9.4	)%	(8.4	)%
Return to provision adjustment	(0.2	)%	(0.4	)%	(0.2	)%

	3.4	%	10.8	%	2.9	%

Schedule of components of deferred tax assets and liabilities

	As at December 31
	2015		2016
Deferred tax assets:
Bad debt provision	539		—
Government subsidy	4,067		3,763
Accrued expenses	8,732		23,324
Asset retirement obligation	1,444		2,377
Net operating loss carry forwards	135,878		141,749

Total gross deferred tax assets	150,660		171,213
Valuation allowance on deferred tax assets	(118,952	)	(134,935	)

Deferred tax assets, net of valuation allowance	31,708		36,278


Deferred tax liabilities:
Property and equipment	(37,982	)	(36,644	)
Intangible assets	(11,430	)	(22,914	)
Prepaid land use rights	(1,774	)	(1,733	)
Obligation under capital lease and other financing obligations	(10,657	)	(15,641	)

Total deferred tax liabilities	(61,843	)	(76,932	)


Net deferred tax liabilities	(30,135	)	(40,654	)


Analysis as:
Current deferred tax assets (note 4)	5,193		—
Non-current deferred tax assets	2,363		12,626
Non-current deferred tax liabilities	(37,691	)	(53,280	)

Net deferred tax liabilities	(30,135	)	(40,654	)

Schedule of movement of the valuation allowance for the deferred tax assets

	Years ended December 31,
	2014		2015	2016

Balance at the beginning of the year	117,065		116,403	118,952
(Decrease) increase during the year	(662	)	2,549	15,983

Balance at the end of the year	116,403		118,952	134,935

LOSS PER ORDINARY SHARE (Tables)

12 Months Ended

Dec. 31, 2016

LOSS PER ORDINARY SHARE

Schedule of computation of basic and diluted loss per share

	Years ended December 31,
	2014		2015		2016
Net loss	129,999		98,584		276,412

Extinguishment of redeemable preferred shares upon repurchase and exchange	106,515		—		—
Change in redemption value of redeemable preferred shares (i)	69,116		110,926		(205,670	)
(Cumulative) Dividend on preferred shares (ii)	3,509		7,127		332,660


Net loss attributable to ordinary shareholders	309,139		216,637		403,402


Weighted average number of ordinary shares outstanding-basic and diluted	162,070,745		217,987,922		299,093,937

Loss per ordinary share - basic and diluted	(1.91	)	(0.99	)	(1.35	)

Schedule of securities excluded from the computation of diluted loss per share

	Years ended December 31,
	2014	2015	2016
Share options/restricted shares	17,463,207	17,193,534	41,499,862
Convertible bonds payable	—	59,692,156	93,977,837
Redeemable preferred shares	349,087,677	349,087,677	—

Total	366,550,884	425,973,367	135,477,699

COMMITMENTS (Tables)

12 Months Ended

Dec. 31, 2016

COMMITMENTS

Schedule of Capital commitments outstanding not provided for in the financial statements

	As at December 31, 2015	As at December 31, 2016

Contracted for	272,958	510,999

RELATED PARTY TRANSACTIONS (Tables)

12 Months Ended

Dec. 31, 2016

RELATED PARTY TRANSACTIONS

Schedule of material related party relationship

In 2014, 2015 and 2016, the related parties of the Company are as follows:

Name of party (note i)		Relationship

William Wei Huang (Mr. Huang)		Director and CEO of the Company
STT GDC Pte. Ltd.		Principal preferred shareholder of the Company
Global Data Solutions Ltd.		Principal ordinary shareholder of the Company

SBCVC Holdings Limited (“SBCVC”)		Principal preferred shareholder of the Company

EDC Holding		SBCVC was a common principal preferred shareholder of both GDS Holdings and EDC Holding prior to the acquisition

Notes (i): The English translation of the company names is for reference only. The official names of the companies established in the PRC are in Chinese.

Schedule of major transactions with related parties

		Years ended December 31,
		2014	2015	2016

Service fees charged by EDC Holding	26(b)(i)	55,869	—	—


Loans made to EDC Holding	26(b)(i)	307,048	—	—


Interest income	26(b)(i)	4,296	—	—


Repurchase of redeemable preferred shares	26(b)(ii)	273,562	—	—


Preference dividends STT GDC Pte. Ltd	26(b)(iii)	—	—	223,225
SBCVC		—	—	109,665
Other non-principal preferred shareholders		—	—	10,406

		—	—	343,296


Loan from a related party	26(b)(iv)	—	64,936	—


Repayment of a related party loan	26(b)(iv)	—	—	65,474


Convertible bonds from a related party	26(b)(iv)	—	—	327,580


Interest expenses STT GDC Pte. Ltd	26(b)(iv)	—	2,579	32,245
EDC Holding	26(b)(i)	244	—	—

		244	2,579	32,245

During the six-month period ended June 30, 2014, the Company provided loans to EDC Holding amounting to RMB307,048. Interest income on the loans amounted to RMB4,296.

In January 2013, EDC Holding provided a loan of US$8,000 (RMB49,222) to the Company. During the six-month period ended June 30, 2014, interest expenses on the loan amounted to RMB 244.

As of December 31, 2015, the amount due to STT GDC Pte. Ltd. comprised US$10,000 (RMB64,936) short-term loan and accrued loan interest of US$397 (RMB2,668).

During the year ended December 31, 2016, the related interest expense arising from the Convertible Bonds due 2019 subscribed by STT GDC Pte. Ltd. amounted to RMB32,245.

Schedule of balances with related parties

		As at December 31
	Note	2015	2016
Amount due to:
STT GDC Pte. Ltd.	26(b)(iv)	67,604	—

		67,604	—

As of December 31, 2015, the amount due to STT GDC Pte. Ltd. comprised US$10,000 (RMB64,936) short-term loan and accrued loan interest of US$397 (RMB2,668).

During the year ended December 31, 2016, the related interest expense arising from the Convertible Bonds due 2019 subscribed by STT GDC Pte. Ltd. amounted to RMB32,245.

PARENT ONLY FINANCIAL INFORMATION (Tables)

12 Months Ended

Dec. 31, 2016

Parent Company

Schedule of condensed financial statements

Condensed Balance Sheets

	As at December 31
	2015		2016
Assets
Current assets
Cash	643,926		1,030,627
Prepaid expenses	—		1,011

Total current assets	643,926		1,031,638

Investment and loans to subsidiaries	2,152,027		3,054,835
Other non-current assets	—		15,856

Total assets	2,795,953		4,102,329


Liabilities and Shareholders’ Equity (Deficit)

Current liabilities
Accrued expenses and other payables	3,782		23,266
Due to subsidiaries	20,890		927
Due to a related party	67,604		—

Total current liabilities	92,276		24,193

Convertible bonds payable	648,515		1,040,550
Other long-term liabilities	353		51,112

Total liabilities	741,144		1,115,855


Redeemable preferred shares (US$0.00005 par value; 350,563,436 shares authorized; 349,087,677 shares issued and outstanding and aggregate redemption amount of RMB2,277,059 as of December 31, 2015)	2,395,314		—

Shareholders’ equity (deficit)
Ordinary shares (US$0.00005 par value; 675,636,564 and 2,002,000,000 shares authorized; 217,987,922 and 760,009,043 shares issued and outstanding as of December 31, 2015 and 2016, respectively))	76		260
Additional paid-in capital	303,621		4,036,959
Accumulated other comprehensive loss	(61,949	)	(192,080	)
Accumulated deficit	(582,253	)	(858,665	)

Total shareholders’ equity (deficit)	(340,505	)	2,986,474

Commitments and contingencies

Total liabilities, redeemable preferred shares and shareholders’ equity (deficit)	2,795,953		4,102,329

Condensed Statements of Operations

	Years ended December 31,
	2014		2015		2016

Net revenue	—		—		—
Cost of revenue	—		—		(2,381	)

Gross profit	—		—		(2,381	)

Operating expenses
Selling and marketing expenses	(2,387	)	(1,566	)	(8,914	)
General and administrative expenses	(32,166	)	(14,665	)	(82,794	)
Research and development expenses	—		—		(52	)

Loss from operations	(34,553	)	(16,231	)	(94,141	)

Other income (expenses):
Interest income	80		—		16
Interest expenses	(35,192	)	(3,297	)	(97,603	)
Gain on remeasurement of equity investment	62,506		—		—
Equity in loss of subsidiaries	(122,742	)	(79,056	)	(84,952	)
Others, net	(98	)	—		268

Loss before income taxes	(129,999	)	(98,584	)	(276,412	)

Income tax expenses	—		—		—

Net loss	(129,999	)	(98,584	)	(276,412	)

Condensed Statements of Comprehensive Loss

	Years ended December 31,
	2014		2015		2016

Net loss	(129,999	)	(98,584	)	(276,412	)
Other comprehensive income (loss):
Foreign currency translation adjustments, net of nil tax	4,114		(118,491	)	(130,131	)

Comprehensive loss	(125,885	)	(217,075	)	(406,543	)

Condensed Statements of Cash Flows

	Years ended December 31,
	2014		2015		2016

Operating activities:
Net cash used in operating activities	(6,609	)	(4,895	)	(62,591	)


Investing activities
Investment in a subsidiary	(92,300	)	—		—
Deposit paid for a potential acquisition	—		—		(15,000	)
Increase of due from subsidiaries	(925,539	)	(93,101	)	(990,617	)

Net cash used in investing activities	(1,017,839	)	(93,101	)	(1,005,617	)

Financing activities:
Proceeds from issuance of convertible bonds	—		648,950		327,580
Proceeds from issuance of bonds payable	114,950		—		—
Repayment of bonds payable	(4,081	)	(14,330	)	—
Proceeds from a related party loan	—		64,936		—
Repayment of a related party loan	—		—		(65,474	)
Proceeds from issuance of Series C redeemable preferred shares	1,521,295		—		—
Payment of issuance costs of Series C redeemable preferred shares	(20,128	)	—		—
Net proceeds from issuance of ordinary shares for initial public offering	—		—		1,221,518
Payment of preferred shares dividends	—		—		(76,502	)
Repurchase of ordinary shares	(119,664	)	—		—
Repurchase of redeemable preferred shares	(455,366	)	(23,300	)	—

Net cash provided by financing activities	1,037,006		676,256		1,407,122
Effect of exchange rate changes on cash	(4,459	)	57,565		47,787


Net increase in cash	8,099		635,825		386,701
Cash at beginning of year	2		8,101		643,926

Cash at end of year	8,101		643,926		1,030,627


Supplemental disclosures of cash flow information
Interest paid	1,317		3,463		45,495

Supplemental disclosures of non-cash investing and financing activities
Issuance of ordinary shares to settle preference dividend	—		—		266,794
Issuance of ordinary shares in exchange of bonds payable	205,536		—		—
Issuance of ordinary and preferred shares for the acquisition of EDC Holding	1,184,242		—		—

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Details) $ / shares in Units, ¥ in Thousands, $ in Thousands			12 Months Ended
	Dec. 06, 2016 USD ($) shares	Nov. 07, 2016 USD ($) $ / shares shares	Dec. 31, 2016 CNY (¥)
Basis of presentation
Issuance of ordinary shares - initial public offering \| ¥			¥ 1,221,518
ADS
Basis of presentation
Initial public offering price (dollar per share) \| $ / shares		$ 10.00
IPO \| ADS
Basis of presentation
Ordinary shares issued (in shares)		19,250,000
Initial public offering price (dollar per share) \| $ / shares		$ 10.00
Issuance of ordinary shares - initial public offering \| $		$ 192,500
IPO \| Class A
Basis of presentation
Ordinary shares issued (in shares)		154,000,000
Over-Allotment Option \| ADS
Basis of presentation
Ordinary shares issued (in shares)	820,735
Issuance of ordinary shares - initial public offering \| $	$ 8,207
Over-Allotment Option \| Class A
Basis of presentation
Ordinary shares issued (in shares)	6,565,880

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
VIEs financial information
Net revenue	¥ 1,055,960	¥ 703,636	¥ 468,337
Net income (loss)	(276,412)	(98,584)	(129,999)
Net cash (used in) provided by operating activities	(150,228)	(80,298)	27,937
Net cash used in investing activities	(1,147,064)	(731,905)	(523,749)
Net cash provided by financing activities	2,128,614	1,127,685	1,056,287
VIEs
VIEs financial information
Loans to be issued to shareholders for equity contribution	¥ 310,100
Loans issued to shareholders for equity contribution, Prior notice period	30 days
Net revenue	¥ 846,168	30,598	9,244
Net income (loss)	22,246	(5,327)	(4,799)
Net cash (used in) provided by operating activities	239,624	8,631	(1,034)
Net cash used in investing activities	(158,681)	¥ (1,456)	¥ (20)
Net cash provided by financing activities	¥ 304,973

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property and equipment (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property and equipment
Depreciation	¥ 212,873	¥ 135,864	¥ 77,946
Buildings \| Minimum
Property and equipment
Estimated useful life (in years)	20 years
Buildings \| Maximum
Property and equipment
Estimated useful life (in years)	30 years
Machinery \| Minimum
Property and equipment
Estimated useful life (in years)	10 years
Machinery \| Maximum
Property and equipment
Estimated useful life (in years)	20 years
Other equipment \| Minimum
Property and equipment
Estimated useful life (in years)	3 years
Other equipment \| Maximum
Property and equipment
Estimated useful life (in years)	5 years
Furniture and office equipment \| Minimum
Property and equipment
Estimated useful life (in years)	3 years
Furniture and office equipment \| Maximum
Property and equipment
Estimated useful life (in years)	5 years
Vehicles
Property and equipment
Estimated useful life (in years)	5 years
Construction in progress
Property and equipment
Depreciation	¥ 0

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Long-lived assets held for sale (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Long-lived assets held for sale
Property held for sale	¥ 18,531	¥ 18,531
Other current assets
Long-lived assets held for sale
Revenue or income recognized on sale of property held for sale	0	¥ 0	¥ 0
Property held for sale	¥ 9,075

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Asset retirement costs (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Activity of the asset retirement obligation liability
Asset retirement obligations at beginning of the period	¥ 5,775	¥ 2,221
Additions	2,942	3,299	¥ 2,148
Accretion expense	588	255	73
Asset retirement obligations at end of the period	¥ 9,305	¥ 5,775	¥ 2,221

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Intangible assets (Details)	12 Months Ended
	Dec. 31, 2016
Customer relationships \| Minimum
Intangible assets
Weighted-average amortization period (in years)	5 years
Customer relationships \| Maximum
Intangible assets
Weighted-average amortization period (in years)	8 years
Favorable lease
Intangible assets
Weighted-average amortization period (in years)	20 years

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Prepaid land use rights (Details)	12 Months Ended
	Dec. 31, 2016
Prepaid land use rights
Prepaid land use rights
Estimated useful life (in years)	50 years

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Goodwill (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Impairment losses	¥ 0	¥ 0	¥ 0

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Impairment of long-lived assets (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Impairment losses for long-lived assets	¥ 0	¥ 0	¥ 0

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Value-added-tax ("VAT") (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Nontrade Receivables
Value-added-tax ("VAT") recoverable	¥ 72,958	¥ 59,680
VAT recoverable, non-current	98,863	0
Accrued expenses and other payables
Nontrade Receivables
VAT payables	¥ 5,954	¥ 2,962

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue recognition (Details)	12 Months Ended
	Dec. 31, 2016
Minimum \| Colocation services
Revenue recognition
Contract service period	1 year
Minimum \| Managed hosting services
Revenue recognition
Contract service period	1 year
Minimum \| Managed cloud services
Revenue recognition
Contract service period	1 year
Maximum \| Colocation services
Revenue recognition
Contract service period	6 years
Maximum \| Managed hosting services
Revenue recognition
Contract service period	6 years
Maximum \| Managed cloud services
Revenue recognition
Contract service period	3 years
Maximum \| Consulting services
Revenue recognition
Contract service period	1 year

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Research and development and advertising costs, Start-up costs, Government grants, Capitalized interest and Debt issuance cost (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Research and development and advertising costs
Research and development expenses	¥ 9,100	¥ 3,554	¥ 1,597
Advertising costs	8,942	4,128	2,363
Capitalized interest
Total interest costs	324,085	138,260	136,458
Less: interest costs capitalized	(58,851)	(11,359)	(4,550)
Interest expenses	265,234	126,901	131,908
Other long-term liabilities
Government grants
Deferred government grants	14,051	16,268
General and administrative expenses
Start-up costs
Pre-operating or start-up costs incurred prior to operating a new data center	12,976	25,659	¥ 16,217
ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs \| Adjustment
Debt issuance cost
Debt issuance costs	¥ 74,246	¥ 23,908

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Employee benefits (Details)	12 Months Ended
	Dec. 31, 2016
Minimum
Employee benefits
Employer contribution (as a percent)	28.00%
Maximum
Employee benefits
Employer contribution (as a percent)	49.00%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Foreign currency translation and foreign currency risks (Details) € in Thousands, ¥ in Thousands, ¥ in Thousands, $ in Thousands, $ in Thousands	Dec. 31, 2016 USD ($)	Dec. 31, 2016 JPY (¥)	Dec. 31, 2016 HKD ($)	Dec. 31, 2016 EUR (€)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)
Cash and restricted cash					¥ 501,125	¥ 200,004
RMB
Cash and restricted cash					501,125
USD
Cash and restricted cash	$ 191,083				1,325,547
HKD
Cash and restricted cash			$ 12,546		11,222
JPY
Cash and restricted cash		¥ 6,592			394
EUR
Cash and restricted cash				€ 96	704
PRC \| RMB
Cash and restricted cash					491,631
PRC \| USD
Cash and restricted cash \| $	32,783
Hong Kong \| RMB
Cash and restricted cash					¥ 9,494
Hong Kong \| USD
Cash and restricted cash \| $	153,307
Hong Kong \| HKD
Cash and restricted cash \| $			$ 12,546
Hong Kong \| JPY
Cash and restricted cash		¥ 6,592
Hong Kong \| EUR
Cash and restricted cash \| €				€ 96
Cayman Island \| USD
Cash and restricted cash \| $	$ 4,993

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recently Issued Accounting Standards (Details) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016 CNY (¥)
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Term of the operating lease commitment, maximum	20 years
Future minimum lease payments	¥ 838,213

ACCOUNTS RECEIVABLES, NET (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2014	Dec. 31, 2015
Accounts receivables
Accounts receivables	¥ 198,851		¥ 113,169
Less: allowance for doubtful accounts			(2,156)
Accounts receivables, net	198,851		111,013
Unbilled portion	117,192		46,275
Movement of the allowance for doubtful accounts
Balance at the beginning of the year	2,156
Allowance made during the year		¥ 2,156
Reversal during the year	(2,156)
Balance at the end of the year		¥ 2,156
Accounts receivable
Accounts receivables
Assets pledged	¥ 87,347		¥ 42,511

OTHER CURRENT ASSETS (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Other current assets
Rental and other deposits	¥ 30,136	¥ 9,456
Deferred tax assets, current (note 20)		5,193
Assets held for sale	18,531	18,531
Others	484	508
Total other current assets	49,151	¥ 33,688
Property
Other current assets
Assets held for sale	9,075
IT equipment
Other current assets
Assets held for sale	¥ 9,456

PROPERTY AND EQUIPMENT, NET (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
At cost:
Property and equipment, gross	¥ 4,239,158	¥ 2,529,644
Less: Accumulated depreciation	(613,658)	(421,475)
Property and equipment net excluding construction in process	3,625,500	2,108,169
Construction in progress	697,391	404,518
Property and equipment, net	4,322,891	2,512,687
Buildings
At cost:
Property and equipment, gross	1,652,641	1,049,376
Data center equipment
At cost:
Property and equipment, gross	1,349,069	891,089
Leasehold improvement
At cost:
Property and equipment, gross	1,202,979	554,450
Furniture and office equipment
At cost:
Property and equipment, gross	31,270	32,001
Vehicles
At cost:
Property and equipment, gross	¥ 3,199	¥ 2,728

PROPERTY AND EQUIPMENT, NET - Acquired under capital leases (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
At cost:
Capital leased assets, gross	¥ 1,312,454	¥ 640,592
Less: Accumulated depreciation	(64,151)	(32,061)
Capital leases, balance sheet, Assets by major class, net, total	1,248,303	608,531
Buildings
At cost:
Capital leased assets, gross	1,286,079	627,874
Asset under construction
At cost:
Capital leased assets, gross	313,721	205,000
Data center equipment
At cost:
Capital leased assets, gross	¥ 26,375	¥ 12,718

PROPERTY AND EQUIPMENT, NET - Depreciation (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Depreciation expense
Depreciation of property and equipment	¥ 212,873	¥ 135,864	¥ 77,946
Cost of revenue
Depreciation expense
Depreciation of property and equipment	206,724	131,097	71,024
General and administrative expenses
Depreciation expense
Depreciation of property and equipment	5,425	¥ 4,767	¥ 6,922
Research and development expenses
Depreciation expense
Depreciation of property and equipment	¥ 724

PROPERTY AND EQUIPMENT, NET - Other information (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
PROPERTY AND EQUIPMENT, NET
Payables for purchase of property and equipment due beyond one year	¥ 37,126	¥ 31,152
Property and equipment, net
PROPERTY AND EQUIPMENT, NET
Net book value of an asset pledged as security for bank loans	¥ 512,566	¥ 579,524

INTANGIBLE ASSETS, NET (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
INTANGIBLE ASSETS, NET (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Intangible assets
Intangible assets, gross	¥ 119,822	¥ 60,322
Less: accumulated amortization	(27,253)	(13,387)
Intangible assets, net	92,569	46,935
Amortization of intangible assets	13,866	8,925	¥ 4,462
Estimated future amortization expense
2017	16,939
2018	16,939
2019	16,939
2020	8,789
2021	8,789
Thereafter	24,174
Intangible assets, net	92,569	46,935
Customer relationships
Intangible assets
Intangible assets, gross	104,322	44,822
Favorable lease
Intangible assets
Intangible assets, gross	¥ 15,500	¥ 15,500

PREPAID LAND USE RIGHTS (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
PREPAID LAND USE RIGHTS (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Prepaid land use rights	¥ 28,370	¥ 28,370
Less: Accumulated amortization	(1,578)	(962)
Prepaid land use rights, net	26,792	27,408
Amortization of prepaid land use rights	616	617	¥ 345
Prepaid land use rights
Net book value of an asset pledged as security for bank loans	¥ 20,735	¥ 20,983

BUSINESS COMBINATION - Movement of goodwill (Details) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016 CNY (¥)
Movement of goodwill
Balance at the beginning of the year	¥ 1,294,664
Addition during the year	46,423
Balance at end of year	¥ 1,341,087

BUSINESS COMBINATION - Consideration (Details) ¥ in Thousands			1 Months Ended
	Jun. 30, 2014 $ / shares shares	May 31, 2014 shareholder	Jun. 30, 2014 $ / shares shares	Nov. 07, 2016 $ / shares	Jun. 30, 2014 CNY (¥)
Ordinary Shares
BUSINESS COMBINATION
Fair value of share issued per share \| $ / shares				$ 1.25
EDC Holding
BUSINESS COMBINATION
Ownership percentage		7.00%
Number of shareholders or any other ordinary or preferred shareholders individually or as a group acting in concert held more than 50% of the voting interest in the Company and EDC Holding \| shareholder		0
Total fair value of total consideration transferred \| ¥					¥ 1,184,242
EDC Holding \| Ordinary Shares
BUSINESS COMBINATION
Number of shares issued as acquisition consideration	88,352,558		88,352,558
Total fair value of total consideration transferred \| ¥					472,945
Fair value of share issued per share \| $ / shares	$ 0.87		$ 0.87
EDC Holding \| Redeemable preferred shares
BUSINESS COMBINATION
Number of shares issued as acquisition consideration	110,810,606
Total fair value of total consideration transferred \| ¥					¥ 711,297
EDC Holding \| Redeemable preferred shares \| Minimum
BUSINESS COMBINATION
Fair value of share issued per share \| $ / shares	$ 0.93		0.93
EDC Holding \| Redeemable preferred shares \| Maximum
BUSINESS COMBINATION
Fair value of share issued per share \| $ / shares	1.13		1.13
EDC Holding \| Redeemable preferred shares \| Average
BUSINESS COMBINATION
Fair value of share issued per share \| $ / shares	$ 1.04		$ 1.04
EDC Holding \| Series A*
BUSINESS COMBINATION
Number of shares issued as acquisition consideration	14,149,705
EDC Holding \| Series B1
BUSINESS COMBINATION
Number of shares issued as acquisition consideration	33,959,293
EDC Holding \| Series B2
BUSINESS COMBINATION
Number of shares issued as acquisition consideration	25,618,413
EDC Holding \| Series B3
BUSINESS COMBINATION
Number of shares issued as acquisition consideration	14,045,432
EDC Holding \| Series B4
BUSINESS COMBINATION
Number of shares issued as acquisition consideration	23,037,763

BUSINESS COMBINATION - Assets acquired (Details) ¥ in Thousands, $ in Thousands						1 Months Ended		6 Months Ended	7 Months Ended	12 Months Ended
	May 19, 2017 CNY (¥)	May 19, 2016 CNY (¥)	Jun. 30, 2014 CNY (¥)	Jun. 29, 2014 USD ($)	Jun. 29, 2014 CNY (¥)	May 31, 2016 CNY (¥)	Feb. 29, 2016 CNY (¥)	Dec. 31, 2014 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)	Dec. 31, 2014 CNY (¥)
Recognized amounts of identifiable assets acquired and liabilities assumed
Goodwill								¥ 1,294,664	¥ 1,341,087	¥ 1,341,087	¥ 1,294,664	¥ 1,294,664
Gain on remeasurement of equity investment												62,506
Proceeds from a related party loan											64,936
Due to a related party											67,604
Net revenue										1,055,960	703,636	468,337
Net income (loss)										¥ (276,412)	¥ (98,584)	¥ (129,999)
EDC Holding
The identifiable assets acquired and liabilities assumed in the business combination
Fair value of consideration transferred			¥ 1,184,242
Fair value of non-controlling equity interest previously held by the Company			62,506
Sub-total			1,246,748
Effective settlement of pre-existing relationships			549,521
Recognized amounts of identifiable assets acquired and liabilities assumed
Cash			(40,999)
Property and equipment			(1,535,246)
Identifiable intangible assets			(60,322)
Other assets			(96,508)
Short-term borrowings and current portion of long-term borrowings			178,638
Accounts payable			290,326
Obligations under capital leases, current			35,234
Long-term borrowings, excluding current portion			342,130
Deferred tax liabilities			45,748
Obligations under capital leases, non-current			250,318
Other liabilities			89,076
Total identifiable net assets			(501,605)
Goodwill			1,294,664
Gain or loss recognized from the effective settlement			0
Gain on remeasurement of equity investment			62,506
Outstanding loans from related party					¥ 344,110
Proceeds from a related party loan				$ 8,000	49,222
Net revenue								17,880
Net income (loss)								¥ (99,949)
EDC Holding \| Buildings
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(624,090)
EDC Holding \| Capital lease
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(422,874)
EDC Holding \| Data center equipment
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(299,801)
EDC Holding \| Leasehold improvement
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(2,694)
EDC Holding \| Furniture and office equipment
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(958)
EDC Holding \| Vehicles
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(749)
EDC Holding \| Construction in progress
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(184,080)
WTENG
The identifiable assets acquired and liabilities assumed in the business combination
Fair value of consideration transferred		¥ 129,500
Consideration paid						¥ 103,600
Effective settlement of pre-existing relationships		43,161
Recognized amounts of identifiable assets acquired and liabilities assumed
Cash		(1,237)
Property and equipment		(281,437)
Identifiable intangible assets		(59,500)
Other assets		(25,363)
Accounts payable		131,114
Capital lease and other financing obligations, current		12,097
Capital lease and other financing obligations, non-current		68,584
Deferred tax liabilities		21,143
Other liabilities		8,361
Total identifiable net assets		(126,238)
Goodwill		46,423
Short-term loans lent to WTENG		42,000				¥ 2,000	¥ 40,000
Interest rate (as a percent)						10.00%	10.00%
Gain or loss recognized from the effective settlement		0
Amount due from WTENG, including interest receivable		43,161
Interest receivable		1,161
Net revenue									36,924
Net income (loss)									¥ (2,861)
WTENG \| Forecast
The identifiable assets acquired and liabilities assumed in the business combination
Consideration paid	¥ 25,900
WTENG \| Capital lease
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment		(102,785)
WTENG \| Data center equipment
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment		(19,895)
WTENG \| Leasehold improvement
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment		(132,462)
WTENG \| Construction in progress
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment		(26,295)
Consolidation eliminations \| EDC Holding
Recognized amounts of identifiable assets acquired and liabilities assumed
Due from related party			598,743
Due to a related party			49,222
Prepayment for future services \| EDC Holding
Recognized amounts of identifiable assets acquired and liabilities assumed
Due from related party					¥ 254,633
Customer relationships \| EDC Holding
Recognized amounts of identifiable assets acquired and liabilities assumed
Identifiable intangible assets			(44,822)
Customer relationships \| WTENG
Recognized amounts of identifiable assets acquired and liabilities assumed
Identifiable intangible assets		¥ (59,500)
Favorable lease \| EDC Holding
Recognized amounts of identifiable assets acquired and liabilities assumed
Identifiable intangible assets			¥ (15,500)
Estimated useful life (in years)			20 years
Minimum \| Customer relationships \| EDC Holding
Recognized amounts of identifiable assets acquired and liabilities assumed
Estimated useful life (in years)			5 years
Minimum \| Customer relationships \| WTENG
Recognized amounts of identifiable assets acquired and liabilities assumed
Estimated useful life (in years)		7 years
Maximum \| Customer relationships \| EDC Holding
Recognized amounts of identifiable assets acquired and liabilities assumed
Estimated useful life (in years)			6 years
Maximum \| Customer relationships \| WTENG
Recognized amounts of identifiable assets acquired and liabilities assumed
Estimated useful life (in years)		8 years

OTHER NON-CURRENT ASSETS (Details) - CNY (¥) ¥ in Thousands	1 Months Ended
OTHER NON-CURRENT ASSETS (Details) - CNY (¥) ¥ in Thousands	Apr. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
OTHER NON-CURRENT ASSETS
Deposits for leases		¥ 62,985	¥ 46,423
Other deposits	¥ 15,000	15,000
Others		20,740	11,093
Total other non-current assets		98,725	57,516
Period from date of memorandum, partial refund of deposits if the acquisition is not consummated	24 months
Deposit amount will be refunded if not consummated within 24 months	¥ 5,000
Other current assets
OTHER NON-CURRENT ASSETS
Deposits for leases		¥ 62,985	¥ 46,423

LOANS AND BORROWINGS - Total loans and borrowings (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Loans and borrowings
Short-term borrowings	¥ 239,777	¥ 333,000
Current portion of long-term borrowings	388,701	95,218
Sub-total	628,478	428,218
Long-term borrowings, excluding current portion	1,509,676	958,264
Total loans and borrowings	¥ 2,138,154	¥ 1,386,482

LOANS AND BORROWINGS - Type of short-term borrowings (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Short-term borrowings by type
Unsecured short-term loans and borrowings		¥ 60,000
Secured short-term loans and borrowings	¥ 239,777	273,000
Short-term borrowings	¥ 239,777	¥ 333,000

LOANS AND BORROWINGS - Short-term borrowings secured (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Short-term borrowings
Assets to secure short-term loans and borrowings	¥ 19,914	¥ 179,363
Weighted average interest rates of short-term borrowings	5.27%	6.55%	6.98%
Short-term loans guaranteed by William Wei Huang, Director and CEO of the Company	¥ 0	¥ 247,000
Accounts receivable
Short-term borrowings
Assets to secure short-term loans and borrowings	¥ 19,914	20,221
Property and equipment, net
Short-term borrowings
Assets to secure short-term loans and borrowings		144,540
Prepaid land use rights
Short-term borrowings
Assets to secure short-term loans and borrowings		¥ 14,602

LOANS AND BORROWINGS - Long-term borrowings (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Long-term borrowings by type
Unsecured long-term loans and borrowings		¥ 2,844
Secured long-term loans and borrowings	¥ 1,898,377	1,050,638
Long-term borrowings	¥ 1,898,377	¥ 1,053,482
Weighted average interest rates of long-term borrowings	8.16%	8.73%	10.20%

LOANS AND BORROWINGS - Long-term borrowings secured (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Loans and Borrowings
Assets to secure long-term loans and borrowings	¥ 600,734	¥ 463,655
Long-term loans guaranteed by William Wei Huang, Director and CEO of the Company	9,500	194,955
Accounts receivable
Loans and Borrowings
Assets to secure long-term loans and borrowings	67,433	22,290
Property and equipment, net
Loans and Borrowings
Assets to secure long-term loans and borrowings	512,566	434,984
Prepaid land use rights
Loans and Borrowings
Assets to secure long-term loans and borrowings	¥ 20,735	¥ 6,381

LOANS AND BORROWINGS - Aggregate maturities (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fiscal year ending December 31,
2017	¥ 388,701
2018	324,473
2019	385,388
2020	359,179
2021	412,457
Thereafter	28,179
Long-term borrowings	¥ 1,898,377	¥ 1,053,482

LOANS AND BORROWINGS - Particulars of secured long-term loans and borrowings (Details) ¥ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2016 CNY (¥) subsidiary	Dec. 31, 2016 CNY (¥) subsidiary	Dec. 31, 2015 CNY (¥)	Dec. 31, 2009 CNY (¥)	Mar. 31, 2017 CNY (¥)	Sep. 30, 2016 CNY (¥) subsidiary	Dec. 31, 2014 CNY (¥)
Secured long-term loans and borrowings
Secured long-term loans and borrowings	¥ 1,898,377	¥ 1,898,377	¥ 1,050,638
Outstanding loans (net of debt issuance costs)	1,898,377	1,898,377	1,053,482
Long-term loans guaranteed by William Wei Huang, Director and CEO of the Company	9,500	9,500	194,955
Accounts receivable
Secured long-term loans and borrowings
Assets pledged	87,347	87,347	42,511
Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	512,566	512,566	579,524
Prepaid land use rights
Secured long-term loans and borrowings
Assets pledged	20,735	20,735	20,983
Secured long-term loans and borrowings
Secured long-term loans and borrowings
Secured long-term loans and borrowings	9,500	¥ 9,500	64,500
Effective interest rate (as a percent)		5.39%
Long-term loans guaranteed by William Wei Huang, Director and CEO of the Company	9,500	¥ 9,500	¥ 14,500
Secured long-term loans and borrowings \| Minimum
Secured long-term loans and borrowings
Effective interest rate (as a percent)			5.39%
Secured long-term loans and borrowings \| Maximum
Secured long-term loans and borrowings
Effective interest rate (as a percent)			6.46%
Secured long-term loans and borrowings \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	23,376	23,376	¥ 138,420
Subsidiary A \| Entrusted credit facility with the local government
Secured long-term loans and borrowings
Term of loan				13 years
Principal amount of credit facility				¥ 322,000
Outstanding loan amount	189,179	¥ 189,179	225,400
Effective interest rate (as a percent)		4.90%
Subsidiary A \| Entrusted credit facility with the local government \| Prepaid land use rights
Secured long-term loans and borrowings
Assets pledged	6,235	¥ 6,235	6,381
Subsidiary B \| Credit facility with a third party bank
Secured long-term loans and borrowings
Principal amount of credit facility							¥ 200,000
Outstanding loan amount	199,600	¥ 199,600	¥ 199,800
Effective interest rate (as a percent)		18.00%	18.00%
Subsidiary B \| Credit facility with a third party bank \| Minimum
Secured long-term loans and borrowings
Covenants, "Borrowing range" of non entrusted loans	130,000	¥ 130,000	¥ 130,000				130,000
Subsidiary B \| Credit facility with a third party bank \| Maximum
Secured long-term loans and borrowings
Covenants, "Borrowing range" of non entrusted loans	360,000	360,000	360,000				240,000
Covenants, Assets pledged of non entrusted loans							¥ 20,000
Subsidiary B \| Credit facility with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	13,367	13,367	¥ 22,290
Subsidiary C \| Credit facility with a third party bank
Secured long-term loans and borrowings
Term of loan			6 years
Principal amount of credit facility			¥ 290,000
Outstanding loan amount			¥ 180,455
Effective interest rate (as a percent)			5.94%
Subsidiary C \| Credit facility with a third party bank \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged			¥ 154,178
Two Subsidiaries, A \| Loan facilities with third party banks
Secured long-term loans and borrowings
Principal amount of credit facility	650,000	650,000
Outstanding loans (net of debt issuance costs)	¥ 415,048	¥ 415,048	¥ 380,483
Number of subsidiaries entered into loan facilities \| subsidiary	2	2
Early repayment if Singapore Technologies Telemedia Limited of Singapore ceases to own and control, the percentage of equity interest in the Company prior to an initial public offering (IPO)	40.00%	40.00%
Early repayment if Singapore Technologies Telemedia Limited of Singapore ceases to own and control, the percentage of equity interest in the Company after an initial public offering (IPO)	30.00%	30.00%
Early repayment if cease to own and control percentage of the equity interest in the borrowing subsidiaries	100.00%	100.00%
Repay early upon the completion of the Company's IPO	¥ 139,232	¥ 139,232
Amount repaid fully upon the completion of the Company's IPO	99,232	99,232
Amount to be early repaid	¥ 30,000	¥ 30,000
Two Subsidiaries, A \| Loan facilities with third party banks \| Forecast
Secured long-term loans and borrowings
Remaining loan amount agreed to be repaid					¥ 40,000
Two Subsidiaries, A \| Loan facilities with third party banks \| Minimum
Secured long-term loans and borrowings
Effective interest rate (as a percent)		7.72%	6.56%
Two Subsidiaries, A \| Loan facilities with third party banks \| Maximum
Secured long-term loans and borrowings
Effective interest rate (as a percent)		7.82%	6.83%
Two Subsidiaries, A \| Loan facilities with third party banks \| William Wei Huang, Director and CEO of the Company
Secured long-term loans and borrowings
Early repayment if cease to own and control percentage of the equity interest in GDS Beijing	99.96%	99.96%
Two Subsidiaries, A \| Loan facilities with third party banks \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	¥ 13,305	¥ 13,305	¥ 0
Two Subsidiaries, A \| Loan facilities with third party banks \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	153,653	153,653	¥ 142,386
Two Subsidiaries, B \| Loan facilities with third party banks
Secured long-term loans and borrowings
Principal amount of credit facility						¥ 1,135,000
Outstanding loan amount	866,983	866,983
Number of subsidiaries entered into loan facilities \| subsidiary						2
Early repayment if STT Communications Ltd. ceases to directly or indirectly own, the percentage of equity interests of STT GDC Pte. Ltd.						50.10%
Early repayment if STT GDC PTe. Ltd. ceases to own and control, the percentage of equity interest in the Company prior to an initial public offering (IPO)						40.00%
Early repayment if STT GDC PTe. Ltd. ceases to own and control, the percentage of equity interest in the Company after an initial public offering (IPO)						30.00%
Early repayment if cease to own and control percentage of the equity interest in the borrowing subsidiaries						100.00%
Amount to be early repaid						¥ 50,000
Two Subsidiaries, B \| Loan facilities with third party banks \| William Wei Huang, Director and CEO of the Company
Secured long-term loans and borrowings
Early repayment if cease to own and control percentage of the equity interest in GDS Beijing						99.90%
Two Subsidiaries, B \| Loan facilities with third party banks \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	8,185	8,185
Two Subsidiaries, B \| Loan facilities with third party banks \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	110,831	110,831
Two Subsidiaries, B \| Short term working capital loan
Secured long-term loans and borrowings
Outstanding loan amount	12,629	¥ 12,629
Effective interest rate (as a percent)		5.66%
Two Subsidiaries, B \| Long term loans
Secured long-term loans and borrowings
Outstanding loans (net of debt issuance costs)	854,354	¥ 854,354
Two Subsidiaries, B \| Long term loans \| Minimum
Secured long-term loans and borrowings
Effective interest rate (as a percent)		7.02%
Two Subsidiaries, B \| Long term loans \| Maximum
Secured long-term loans and borrowings
Effective interest rate (as a percent)		7.34%
Subsidiary D \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Principal amount of credit facility						¥ 220,000
Outstanding loan amount	137,334	¥ 137,334
Amount to be early repaid						¥ 50,000
Subsidiary D \| Facility Agreement with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	30,110	30,110
Subsidiary D \| Facility Agreement with a third party bank \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	85,765	85,765
Subsidiary D \| Short term working capital loan
Secured long-term loans and borrowings
Outstanding loan amount	12,611	¥ 12,611
Effective interest rate (as a percent)		5.87%
Subsidiary D \| Long term loans
Secured long-term loans and borrowings
Outstanding loans (net of debt issuance costs)	¥ 124,723	¥ 124,723
Effective interest rate (as a percent)		7.63%
Subsidiary E \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Term of loan	18 months
Principal amount of credit facility	¥ 380,000	¥ 380,000
Amount to be early repaid	¥ 30,000	30,000
Subsidiary E \| Facility Agreement with a third party bank \| SHIBOR
Secured long-term loans and borrowings
Interest rate (percentage plus SHIBOR)	3.65%
Subsidiary F \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Principal amount of credit facility	¥ 310,000	310,000
Outstanding loan amount	106,510	106,510
Amount to be early repaid	50,000	50,000
Subsidiary F \| Facility Agreement with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	2,466	2,466
Subsidiary F \| Facility Agreement with a third party bank \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	138,941	138,941
Subsidiary F \| Facility Agreement with a third party bank \| Prepaid land use rights
Secured long-term loans and borrowings
Assets pledged	14,500	14,500
Subsidiary F \| Short term working capital loan
Secured long-term loans and borrowings
Outstanding loan amount	¥ 537	537
Effective interest rate (as a percent)	5.66%
Subsidiary F \| Long term loans
Secured long-term loans and borrowings
Outstanding loans (net of debt issuance costs)	¥ 105,973	¥ 105,973
Effective interest rate (as a percent)	6.32%

LOANS AND BORROWINGS - Particulars of unsecured long-term loans and borrowings (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 CNY (¥)
Unsecured long-term loans and borrowings
Outstanding loan amount \| ¥			¥ 2,844
Unsecured Debt
Unsecured long-term loans and borrowings
Term of loan	2 years
Principal amount of credit facility \| $	$ 5,000
Outstanding loan amount		$ 438	¥ 2,844

LOANS AND BORROWINGS - Total working capital and project financing credit (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Loans and Borrowings
Outstanding loans (net of debt issuance costs)	¥ 1,898,377	¥ 1,053,482
Letter of Credit
Loans and Borrowings
Total working capital and project financing credit facilities	3,181,278
Unused amount	968,878
Loan drew down	2,212,400
Debt issuance costs	74,246
Letter of Credit \| Short-term loans and borrowing
Loans and Borrowings
Outstanding loans (net of debt issuance costs)	239,777
Letter of Credit \| Long-term loans and borrowing
Loans and Borrowings
Outstanding loans (net of debt issuance costs)	¥ 1,898,377

BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE (Details) ¥ / shares in Units, $ / shares in Units, ¥ in Thousands, $ in Thousands													1 Months Ended		12 Months Ended
	Jan. 29, 2016 USD ($)	Jan. 29, 2016 CNY (¥)	Dec. 30, 2015 USD ($) tranche item $ / shares	Dec. 30, 2015 CNY (¥) item	Jun. 10, 2015 USD ($)	Jun. 10, 2015 CNY (¥)	Aug. 13, 2014 $ / shares shares	Aug. 13, 2014 ¥ / shares shares	Jun. 11, 2014 USD ($)	Jun. 11, 2014 CNY (¥)	Jun. 10, 2014 USD ($)	Jun. 10, 2014 CNY (¥)	Aug. 31, 2014 USD ($) $ / shares shares	Aug. 31, 2014 CNY (¥) shares	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)	Dec. 31, 2014 CNY (¥) shares	Dec. 30, 2015 CNY (¥) tranche	Jun. 11, 2014 CNY (¥)	Jun. 10, 2014 CNY (¥)	Dec. 11, 2012 USD ($)	Dec. 11, 2012 CNY (¥)
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Amount repaid																¥ 14,330	¥ 4,081
Issuance of ordinary shares in exchange of bonds payable																	¥ 205,536
Proceeds from convertible bonds															¥ 327,580	648,950
Due to a related party																67,604
Gain or loss on change in fair value of derivative liability															0
STT GDC Pte. Ltd.
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Due to a related party																¥ 67,604
Series C
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Shares issued \| shares							238,526,241	238,526,241					238,526,241	238,526,241			238,526,241
Issuance price per share \| (per share)							$ 1.0365	¥ 6.3779					$ 1.036522
Bonds due 2014
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Principal amount																					$ 10,509	¥ 66,125
Interest per annum (as a percent)																					10.00%	10.00%
Outstanding loan amount											$ 10,509									¥ 64,541
Amount repaid									$ 9,845	¥ 60,460	$ 664	¥ 4,081
Unpaid interest payable paid by Bonds due to 2015										¥ 10,360
Bonds due 2015
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Principal amount									$ 30,203										¥ 185,770
Interest per annum (as a percent)									10.00%										10.00%
Amount repaid					$ 2,343	¥ 14,330
Bond denomination \| $									$ 10
Price used to determine the number of ordinary shares issued in exchange for the bonds, percentage of the QIPO price									70.00%	70.00%
Price used to determine the number of ordinary shares issued in exchange for the bonds, percentage of the issuance price of the private placement									70.00%	70.00%
Total interest expense related to the debt discount														¥ 34,105			¥ 34,105
Debt not converted to ordinary shares													$ 2,343	¥ 14,330
Bonds due 2015 \| Series C
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Price used to determine the number of ordinary shares issued in exchange for the bonds, percentage of the issuance price of the private placement													70.00%	70.00%
Issuance of ordinary shares in exchange of bonds payable													$ 27,860	¥ 171,431
Number of shares issued for converted debt \| shares													38,397,655	38,397,655
Basis of issuance of shares for debt conversion (in dollar per share) \| $ / shares													$ 0.72557
Bonds due 2015 \| Put Option
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Fair value of the embedded put option									$ 5,547										¥ 34,105
Convertible Bonds Due 2019
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Principal amount \| $			$ 250,000
Number of tranches \| tranche			4															4
Interest per annum (as a percent)			10.00%															10.00%
Basis of issuance of shares for debt conversion (in dollar per share) \| $ / shares			$ 1.675262
Number Of Investor \| item			2	2
Proceeds from convertible bonds	$ 50,000	¥ 324,475	$ 100,000	¥ 648,950
Unsubscribed bonds			$ 100,000															¥ 648,950
Maximum principal amount convertible to ordinary shares			100.00%															100.00%
Denominations for conversion of debt \| $			$ 10,000
Minimum percentage of stock price to trigger mandatory conversion			125.00%	125.00%
Premium over conversion price to trigger mandatory conversion			25.00%															25.00%
Convertible Bonds Due 2019 \| Accrued expenses and other payables \| STT GDC Pte. Ltd.
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Accrued interests															1,118
Due to a related party															1,090
Convertible Bonds Due 2019 \| Other long-term liabilities \| STT GDC Pte. Ltd.
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Accrued interests															73,681
Due to a related party															¥ 23,403
Convertible Bonds Due 2019 \| Minimum
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Trading days of stock price to trigger mandatory conversion			10 days	10 days
A Subsidiary \| Convertible Bonds Due 2019
BONDS PAYABLE/CONVERTIBLE BONDS PAYABLE
Equity interest in a subsidiary pledged (as a percent)															100.00%	100.00%

ACCRUED EXPENSES AND OTHER PAYABLES (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
ACCRUED EXPENSES AND OTHER PAYABLES
Accrued rental expenses	¥ 12,744	¥ 12,951
Accrued utility expenses	14,348	8,548
Accrued payroll and welfare benefits	31,165	27,062
Accrued interest expenses	67,324	23,722
Accrued professional service fees	11,867	8,352
Other taxes payables	11,470	14,296
Income tax payable (note 20)	15,265	8,955
Consideration payable for the acquisition of WTENG (note 8)	25,900
Other payables	17,867	14,430
Total accrued expenses and other payables	¥ 207,950	¥ 118,316

LEASE - Capital lease and other financing obligations (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Capital lease obligations
Within 1 year	¥ 71,300	¥ 51,591
After 1 year but within 2 years	85,783	60,019
After 2 years but within 3 years	92,677	64,938
After 3 years but within 4 years	193,202	69,089
After 4 years but within 5 years	71,501	172,079
After 5 years	716,089	395,251
Total minimum lease payments	1,230,552	812,967
Less: total future interest	(552,060)	(339,283)
Present value of the minimum lease payments	678,492	473,684
Other financing obligations
Within 1 year	22,044
After 1 year but within 2 years	38,443
After 2 years but within 3 years	39,548
After 3 years but within 4 years	41,586
After 4 years but within 5 years	42,287
After 5 years	725,178
Total other financing obligations	909,086
Less: total future interest	(450,670)
Less: estimated building costs	(25,356)
Present value of other financing obligations	433,060
Total
Within 1 year	93,344	51,591
After 1 year but within 2 years	124,226	60,019
After 2 years but within 3 years	132,225	64,938
After 3 years but within 4 years	234,788	69,089
After 4 years but within 5 years	113,788	172,079
After 5 years	1,441,267	395,251
Total	2,139,638	812,967
Less: total future interest	(1,002,730)	(339,283)
Less: estimated building costs	(25,356)
Present value of total obligations	1,111,552	473,684
Including:
Current Portion	88,593	48,745
Noncurrent portion	¥ 1,022,959	¥ 424,939
Weighted average effective interest rate of capital and built-to-suit leases (as a percent)	8.04%	8.63%	9.71%

LEASE - Capital lease agreements (Details) ¥ in Thousands	1 Months Ended			5 Months Ended
LEASE - Capital lease agreements (Details) ¥ in Thousands	Oct. 31, 2015	Jul. 31, 2015 CNY (¥) item	Mar. 31, 2015	Jul. 31, 2015 CNY (¥) item	Dec. 31, 2016 CNY (¥)	Jan. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)
Capital leases
Capital lease assets					¥ 1,248,303		¥ 608,531
Present value of minimum lease payments					¥ 678,492		¥ 473,684
Shenzhen 2 Lease and Shenzhen 3 Lease, capital lease
Capital leases
Number of lease agreements \| item				2
Number of buildings leased under capital lease agreement \| item		2		2
Capital lease assets		¥ 205,000		¥ 205,000
Capital lease obligations		205,000		205,000
Present value of minimum lease payments		¥ 205,000		¥ 205,000
Shenzhen 2 Lease, capital lease
Capital leases
Term of capital lease			10 years
Shenzhen 3 Lease, capital lease
Capital leases
Term of capital lease		15 years
Shenzhen 4 Lease, capital lease
Capital leases
Term of capital lease	20 years
Capital lease assets						¥ 138,721
Capital lease obligations						138,721
Present value of minimum lease payments						¥ 138,721

LEASE - Built-to-suit leases (Details) - Shanghai 3 Lease and Shanghai 4 Lease ¥ in Thousands	2 Months Ended
	Feb. 28, 2015 CNY (¥) item
Build-to-suit leases
Number Of Leases	2
Number of buildings leased under built-to-suit lease	2
Term of built-to-suit lease	20 years
Rent paid \| ¥	¥ 0
Percentage of total minimum lease payments due payable on termination of lease	15.00%

LEASE - Operating leases (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
LEASE - Operating leases (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Future minimum operating lease payments
2017	¥ 124,293
2018	98,566
2019	75,657
2020	57,268
2021	36,822
Thereafter	445,607
Total	838,213
Rental expenses	¥ 124,712	¥ 131,875	¥ 110,117

Other long-term liabilities (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Other long-term liabilities
Payables for purchase of property and equipment	¥ 37,126	¥ 31,152
Accrued interests	51,112	25,810
Deferred government grants	14,051	16,268
Others	9,417	5,775
Total other long-term liabilities	¥ 111,706	¥ 79,005

REDEEMABLE PREFERRED SHARES - Movement (Details) - CNY (¥) ¥ in Thousands		1 Months Ended				4 Months Ended	12 Months Ended
	Aug. 13, 2014	Aug. 31, 2014	Jun. 30, 2014	Mar. 31, 2011	Jan. 31, 2007	Dec. 22, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement of the redeemable preferred shares
Balance at beginning of year							¥ 2,395,314
Balance at beginning of year (in shares)							349,087,677
Change in redemption value							¥ 205,670	¥ (110,926)	¥ (69,116)
Conversion to ordinary shares							2,311,132
Balance at end of year								¥ 2,395,314
Balance at end of year (in shares)								349,087,677
Redeemable preferred shares
Movement of the redeemable preferred shares
Balance at beginning of year							¥ 2,395,314	¥ 2,164,039	¥ 262,490
Balance at beginning of year (in shares)							349,087,677	349,087,677	74,800,000
Issuance of redeemable preferred shares - in relation to business combination									¥ 711,297
Issuance of redeemable preferred shares - in relation to business combination (in shares)									110,810,606
Issuance of redeemable preferred shares - third party investor									¥ 1,501,167
Issuance of redeemable preferred shares - third party investor (in shares)									238,526,241
Extinguishment of redeemable preferred shares upon repurchase									¥ (401,766)
Extinguishment of redeemable preferred shares upon repurchase (in shares)									(75,049,170)
Extinguishment of redeemable preferred shares upon exchange									¥ 29,615
Extinguishment of redeemable preferred shares upon exchange (in shares)						(35,393,262)
Change in redemption value							¥ (205,670)	¥ 110,926	69,116
Conversion to ordinary shares							¥ (2,311,132)
Conversion to ordinary shares (in shares)							(349,087,677)
Foreign exchange impact							¥ 121,488	120,349	(7,880)
Balance at end of year								¥ 2,395,314	¥ 2,164,039
Balance at end of year (in shares)								349,087,677	349,087,677
Series A
Movement of the redeemable preferred shares
Balance at beginning of year							¥ 107,428	¥ 97,274	¥ 198,434
Balance at beginning of year (in shares)							29,635,045	29,635,045	63,250,000
Issuance of redeemable preferred shares - third party investor (in shares)					53,625,000
Extinguishment of redeemable preferred shares upon repurchase									¥ (76,473)
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(23,533,064)								(23,533,064)
Extinguishment of redeemable preferred shares upon exchange									¥ (32,803)
Extinguishment of redeemable preferred shares upon exchange (in shares)						(10,081,891)			(10,081,891)
Change in redemption value							¥ (39,098)	¥ 4,029	¥ 6,824
Conversion to ordinary shares							¥ (72,965)
Conversion to ordinary shares (in shares)							(29,635,045)
Foreign exchange impact							¥ 4,635	6,125	1,292
Balance at end of year								¥ 107,428	¥ 97,274
Balance at end of year (in shares)								29,635,045	29,635,045
Series A*
Movement of the redeemable preferred shares
Balance at beginning of year							¥ 39,575	¥ 39,575
Balance at beginning of year (in shares)							6,916,645	6,916,645
Issuance of redeemable preferred shares - in relation to business combination									¥ 80,965
Issuance of redeemable preferred shares - in relation to business combination (in shares)			14,149,705						14,149,705
Extinguishment of redeemable preferred shares upon repurchase									¥ (31,497)
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(5,503,899)								(5,503,899)
Extinguishment of redeemable preferred shares upon exchange									¥ (9,896)
Extinguishment of redeemable preferred shares upon exchange (in shares)						(1,729,161)			(1,729,161)
Conversion to ordinary shares							¥ (43,564)
Conversion to ordinary shares (in shares)							(6,916,645)
Foreign exchange impact							¥ 3,989		¥ 3
Balance at end of year								¥ 39,575	¥ 39,575
Balance at end of year (in shares)								6,916,645	6,916,645
Series B
Movement of the redeemable preferred shares
Balance at beginning of year							¥ 16,789	¥ 15,080	¥ 64,056
Balance at beginning of year (in shares)							2,576,483	2,576,483	11,550,000
Issuance of redeemable preferred shares - third party investor (in shares)				11,550,000
Extinguishment of redeemable preferred shares upon repurchase									¥ (48,593)
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(8,413,412)								(8,413,412)
Extinguishment of redeemable preferred shares upon exchange									¥ (3,276)
Extinguishment of redeemable preferred shares upon exchange (in shares)						(560,105)			(560,105)
Change in redemption value							¥ (3,921)	¥ 754	¥ 2,393
Conversion to ordinary shares							¥ (13,600)
Conversion to ordinary shares (in shares)							(2,576,483)
Foreign exchange impact							¥ 732	955	500
Balance at end of year								¥ 16,789	¥ 15,080
Balance at end of year (in shares)								2,576,483	2,576,483
Series B1
Movement of the redeemable preferred shares
Balance at beginning of year							¥ 80,148	¥ 80,148
Balance at beginning of year (in shares)							11,527,742	11,527,742
Issuance of redeemable preferred shares - in relation to business combination									¥ 236,108
Issuance of redeemable preferred shares - in relation to business combination (in shares)			33,959,293						33,959,293
Extinguishment of redeemable preferred shares upon repurchase									¥ (91,847)
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(13,209,358)								(13,209,358)
Extinguishment of redeemable preferred shares upon exchange									¥ (63,800)
Extinguishment of redeemable preferred shares upon exchange (in shares)									(9,222,193)
Conversion to ordinary shares							¥ (88,221)
Conversion to ordinary shares (in shares)							(11,527,742)
Foreign exchange impact							¥ 8,073		¥ (313)
Balance at end of year								¥ 80,148	¥ 80,148
Balance at end of year (in shares)								11,527,742	11,527,742
Series B2
Movement of the redeemable preferred shares
Balance at beginning of year							¥ 67,419	¥ 67,419
Balance at beginning of year (in shares)							10,435,639	10,435,639
Issuance of redeemable preferred shares - in relation to business combination									¥ 165,506
Issuance of redeemable preferred shares - in relation to business combination (in shares)			25,618,413						25,618,413
Extinguishment of redeemable preferred shares upon repurchase									¥ (64,383)
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(9,964,954)								(9,964,954)
Extinguishment of redeemable preferred shares upon exchange									¥ (33,540)
Extinguishment of redeemable preferred shares upon exchange (in shares)									(5,217,820)
Conversion to ordinary shares							¥ (74,209)
Conversion to ordinary shares (in shares)							(10,435,639)
Foreign exchange impact							¥ 6,790		¥ (164)
Balance at end of year								¥ 67,419	¥ 67,419
Balance at end of year (in shares)								10,435,639	10,435,639
Series B3
Movement of the redeemable preferred shares
Issuance of redeemable preferred shares - in relation to business combination									¥ 85,554
Issuance of redeemable preferred shares - in relation to business combination (in shares)			14,045,432						14,045,432
Extinguishment of redeemable preferred shares upon repurchase									¥ (33,281)
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(5,463,340)								(5,463,340)
Extinguishment of redeemable preferred shares upon exchange									¥ (52,268)
Extinguishment of redeemable preferred shares upon exchange (in shares)									(8,582,092)
Foreign exchange impact									¥ (5)
Series B4
Movement of the redeemable preferred shares
Balance at beginning of year							¥ 87,477	¥ 87,477
Balance at beginning of year (in shares)							14,076,620	14,076,620
Issuance of redeemable preferred shares - in relation to business combination									¥ 143,164
Issuance of redeemable preferred shares - in relation to business combination (in shares)			23,037,763						23,037,763
Extinguishment of redeemable preferred shares upon repurchase									¥ (55,692)
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(8,961,143)								(8,961,143)
Conversion to ordinary shares							¥ (96,287)
Conversion to ordinary shares (in shares)							(14,076,620)
Foreign exchange impact							¥ 8,810		¥ 5
Balance at end of year								¥ 87,477	¥ 87,477
Balance at end of year (in shares)								14,076,620	14,076,620
Series B5
Movement of the redeemable preferred shares
Balance at beginning of year							¥ 258,038	¥ 229,683
Balance at beginning of year (in shares)							35,393,262	35,393,262
Issuance of redeemable preferred shares - third party investor (in shares)						35,393,262
Extinguishment of redeemable preferred shares upon exchange									¥ 225,198
Extinguishment of redeemable preferred shares upon exchange (in shares)									35,393,262
Change in redemption value							¥ (21,016)	¥ 13,715	¥ 5,210
Conversion to ordinary shares							¥ (248,455)
Conversion to ordinary shares (in shares)							(35,393,262)
Foreign exchange impact							¥ 11,433	14,640	(725)
Balance at end of year								¥ 258,038	¥ 229,683
Balance at end of year (in shares)								35,393,262	35,393,262
Series C
Movement of the redeemable preferred shares
Balance at beginning of year							¥ 1,738,440	¥ 1,547,383
Balance at beginning of year (in shares)							238,526,241	238,526,241
Issuance of redeemable preferred shares - third party investor									¥ 1,501,167
Issuance of redeemable preferred shares - third party investor (in shares)	238,526,241	238,526,241							238,526,241
Change in redemption value							¥ (141,635)	¥ 92,428	¥ 54,689
Conversion to ordinary shares							¥ (1,673,831)
Conversion to ordinary shares (in shares)							(238,526,241)
Foreign exchange impact							¥ 77,026	98,629	(8,473)
Balance at end of year								¥ 1,738,440	¥ 1,547,383
Balance at end of year (in shares)								238,526,241	238,526,241

REDEEMABLE PREFERRED SHARES - Issued and Outstanding (Details) ¥ / shares in Units, $ / shares in Units, ¥ in Thousands, $ in Thousands			1 Months Ended						4 Months Ended		12 Months Ended
	Aug. 13, 2014 USD ($) $ / shares shares	Aug. 13, 2014 CNY (¥) ¥ / shares shares	Aug. 31, 2014 $ / shares shares	Jun. 30, 2014 shares	Mar. 31, 2011 $ / shares shares	Mar. 31, 2011 ¥ / shares shares	Jan. 31, 2007 USD ($) $ / shares shares	Jan. 31, 2007 CNY (¥) ¥ / shares shares	Dec. 22, 2014 USD ($) $ / shares shares	Dec. 22, 2014 CNY (¥) ¥ / shares shares	Dec. 31, 2014 CNY (¥) shares	Dec. 31, 2015 CNY (¥) shares	Dec. 31, 2013 CNY (¥) shares
REDEEMABLE PREFERRED SHARES
Shares authorized												350,563,436
Shares issued												349,087,677
Shares outstanding												349,087,677
Carrying amount \| ¥												¥ 2,395,314
Issuance of ordinary shares in exchange of bonds payable \| ¥											¥ 205,536
Issuance costs \| ¥											¥ 20,128
Ordinary Shares
REDEEMABLE PREFERRED SHARES
Acquisition of EDC Holding (in shares)				88,352,558
Redeemable preferred shares
REDEEMABLE PREFERRED SHARES
Shares outstanding											349,087,677	349,087,677	74,800,000
Carrying amount \| ¥											¥ 2,164,039	¥ 2,395,314	¥ 262,490
Shares issued											238,526,241
Shares issued in connection with acquisition											110,810,606
Series A
REDEEMABLE PREFERRED SHARES
Shares outstanding											29,635,045	29,635,045	63,250,000
Carrying amount \| ¥											¥ 97,274	¥ 107,428	¥ 198,434
Shares issued							53,625,000	53,625,000
Issuance price per share \| (per share)							$ 0.3636	¥ 2.8279
Issuance of ordinary shares in exchange of bonds payable							$ 3,500	¥ 27,222
Number of shares issued for converted debt							9,625,000	9,625,000
Series A*
REDEEMABLE PREFERRED SHARES
Shares outstanding											6,916,645	6,916,645
Carrying amount \| ¥											¥ 39,575	¥ 39,575
Shares issued in connection with acquisition				14,149,705							14,149,705
Series B
REDEEMABLE PREFERRED SHARES
Shares outstanding											2,576,483	2,576,483	11,550,000
Carrying amount \| ¥											¥ 15,080	¥ 16,789	¥ 64,056
Shares issued					11,550,000	11,550,000
Issuance price per share \| (per share)					$ 0.7792	¥ 5.1087
Series B1
REDEEMABLE PREFERRED SHARES
Shares outstanding											11,527,742	11,527,742
Carrying amount \| ¥											¥ 80,148	¥ 80,148
Shares issued in connection with acquisition				33,959,293							33,959,293
Series B2
REDEEMABLE PREFERRED SHARES
Shares outstanding											10,435,639	10,435,639
Carrying amount \| ¥											¥ 67,419	¥ 67,419
Shares issued in connection with acquisition				25,618,413							25,618,413
Series B3
REDEEMABLE PREFERRED SHARES
Shares issued in connection with acquisition				14,045,432							14,045,432
Series B4
REDEEMABLE PREFERRED SHARES
Shares outstanding											14,076,620	14,076,620
Carrying amount \| ¥											¥ 87,477	¥ 87,477
Shares issued in connection with acquisition				23,037,763							23,037,763
Series B5
REDEEMABLE PREFERRED SHARES
Shares outstanding											35,393,262	35,393,262
Carrying amount \| ¥											¥ 229,683	¥ 258,038
Shares issued									35,393,262	35,393,262
Issuance price per share \| (per share)									$ 1.0365	¥ 6.3779
Cash consideration for issuance of shares									$ 36,685	¥ 225,198
Series C
REDEEMABLE PREFERRED SHARES
Shares outstanding											238,526,241	238,526,241
Carrying amount \| ¥											¥ 1,547,383	¥ 1,738,440
Shares issued	238,526,241	238,526,241	238,526,241								238,526,241
Issuance price per share \| (per share)	$ 1.0365	¥ 6.3779	$ 1.036522
Cash consideration for issuance of shares	$ 247,238	¥ 1,521,295
Issuance costs	$ 3,271	¥ 20,128

REDEEMABLE PREFERRED SHARES - Extinguishment (Details) ¥ / shares in Units, $ / shares in Units, ¥ in Thousands, $ in Thousands			1 Months Ended					4 Months Ended		12 Months Ended
	Aug. 13, 2014 USD ($) $ / shares shares	Aug. 13, 2014 CNY (¥) ¥ / shares shares	Aug. 31, 2014 $ / shares	Mar. 31, 2011 $ / shares	Mar. 31, 2011 ¥ / shares	Jan. 31, 2007 $ / shares	Jan. 31, 2007 ¥ / shares	Dec. 22, 2014 USD ($) item $ / shares shares	Dec. 22, 2014 CNY (¥) item ¥ / shares shares	Dec. 31, 2015 CNY (¥) shares	Dec. 31, 2014 CNY (¥) shares	Dec. 22, 2014 CNY (¥)	Aug. 13, 2014 CNY (¥)	Dec. 31, 2013 CNY (¥)
REDEEMABLE PREFERRED SHARES
Carrying amount \| ¥										¥ 2,395,314
Shares issued										349,087,677
Redeemable preferred shares
REDEEMABLE PREFERRED SHARES
Number of shares repurchased											75,049,170
Carrying amount \| ¥										¥ 2,395,314	¥ 2,164,039			¥ 262,490
Shares exchanged								35,393,262	35,393,262
Series A
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	23,533,064	23,533,064									23,533,064
Carrying amount \| ¥										107,428	¥ 97,274			198,434
Shares exchanged								10,081,891	10,081,891		10,081,891
Purchase price per share \| (per share)						$ 0.3636	¥ 2.8279
Series A*
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	5,503,899	5,503,899									5,503,899
Carrying amount \| ¥										39,575	¥ 39,575
Shares exchanged								1,729,161	1,729,161		1,729,161
Series B
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	8,413,412	8,413,412									8,413,412
Carrying amount \| ¥										16,789	¥ 15,080			¥ 64,056
Shares exchanged								560,105	560,105		560,105
Purchase price per share \| (per share)				$ 0.7792	¥ 5.1087
Series B1
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	13,209,358	13,209,358									13,209,358
Carrying amount \| ¥										80,148	¥ 80,148
Shares exchanged											9,222,193
Series B2
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	9,964,954	9,964,954									9,964,954
Carrying amount \| ¥										67,419	¥ 67,419
Shares exchanged											5,217,820
Series B3
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	5,463,340	5,463,340									5,463,340
Shares exchanged											8,582,092
Series B4
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	8,961,143	8,961,143									8,961,143
Carrying amount \| ¥										87,477	¥ 87,477
Series B5
REDEEMABLE PREFERRED SHARES
Difference between repurchase price or fair value and carrying amount								$ 4,812	¥ 29,615
Carrying amount \| ¥										258,038	¥ 229,683
Shares exchanged											(35,393,262)
Number of shares sold by holders								35,393,262	35,393,262
Purchase price per share \| (per share)								$ 1.0365	¥ 6.3779
Total cash consideration								$ 36,685	¥ 225,198
Number of investor \| item								1	1
Series C
REDEEMABLE PREFERRED SHARES
Minimum holding of issued share capital	40.00%	40.00%
Carrying amount \| ¥										1,738,440	¥ 1,547,383
Purchase price per share \| (per share)	$ 1.0365	¥ 6.3779	$ 1.036522
Total cash consideration	$ 247,238	¥ 1,521,295
Exchanged Shares
REDEEMABLE PREFERRED SHARES
Carrying amount								$ 31,873				¥ 195,583
Series A, Series A*, Series B, Series B1, Series B2, Series B3 and Series B4
REDEEMABLE PREFERRED SHARES
Repurchase price per share \| (per share)	$ 1.0365	¥ 6.3779
Repurchase cash consideration	$ 77,790	¥ 478,666
Amount paid for shares repurchased \| ¥										¥ 23,300	¥ 455,366
Difference between repurchase price or fair value and carrying amount	12,497	¥ 76,900
Carrying amount	$ 65,293												¥ 401,766
Series B*
REDEEMABLE PREFERRED SHARES
Shares exchanged								23,022,105	23,022,105

REDEEMABLE PREFERRED SHARES - Preference Dividend (Details) $ / shares in Units, ¥ in Thousands, $ in Thousands				12 Months Ended
	Nov. 07, 2016 USD ($) $ / shares shares	Nov. 07, 2016 CNY (¥) shares	Sep. 29, 2016	Dec. 31, 2016 CNY (¥)
Preference Dividend
Preference dividend (as a percent)			6.00%
Preference dividend paid	$ 50,812	¥ 343,296		¥ 343,296
Preference dividend paid in cash	11,449	76,502
Issuance of ordinary shares to settle preference dividend	$ 39,363	¥ 266,794		¥ 266,794
Ordinary shares issued as preferred stock dividends (in shares) \| shares	31,490,164	31,490,164
ADS
Preference Dividend
Initial public offering price (dollar per share)	$ 10.00
Ordinary Shares
Preference Dividend
Initial public offering price (dollar per share)	$ 1.25

REDEEMABLE PREFERRED SHARES - Terms (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 07, 2016	Dec. 31, 2015
Redeemable preferred shares
REDEEMABLE PREFERRED SHARES
Conversion ratio of preferred shares to ordinary share	1	1
Minimum gross cash proceeds in an IPO to trigger automatic conversion to ordinary shares		$ 100,000
Minimum percentage of issue price per share above US1.0365 in an IPO to trigger automatic conversion to ordinary shares		25.00%
Threshold amount in an IPO to trigger automatic conversion to ordinary shares		$ 1.0365
Minimum public float to trigger automatic conversion to ordinary shares (as a percent)		20.00%
Minimum votes required for redemption (as a percent)		75.00%
Cumulative dividend rate		6.00%
Number of shares converted	(349,087,677)
Series A
REDEEMABLE PREFERRED SHARES
Redemption amount per share		$ 0.363636
Series A*
REDEEMABLE PREFERRED SHARES
Redemption amount per share		0.1060
Series B
REDEEMABLE PREFERRED SHARES
Redemption amount per share		0.77922
Series B1
REDEEMABLE PREFERRED SHARES
Redemption amount per share		0.5300
Series B2
REDEEMABLE PREFERRED SHARES
Redemption amount per share		0.5855
Series B4
REDEEMABLE PREFERRED SHARES
Redemption amount per share		0.4340
Series B5
REDEEMABLE PREFERRED SHARES
Redemption amount per share		$ 1.036522
Series C
REDEEMABLE PREFERRED SHARES
Consent to convert preferred shares to ordinary shares (as a percent)		75.00%
Redemption amount per share		$ 1.036522
Series A, Series A*, Series B, Series B1, Series B2, Series B4 and Series B5
REDEEMABLE PREFERRED SHARES
Consent to convert preferred shares to ordinary shares (as a percent)		85.00%
Ordinary Shares
REDEEMABLE PREFERRED SHARES
Number of shares converted	349,087,677

FAIR VALUE MEASUREMENT (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
FAIR VALUE MEASUREMENT
Assets fair value on recurring basis	¥ 0	¥ 0
Liabilities fair value on recurring basis	0	0
Convertible debt, fair value	1,040,550
Convertible debt, carrying amount	¥ 1,040,550	¥ 648,515

ORDINARY SHARES (Details) ¥ / shares in Units, $ / shares in Units, ¥ in Thousands, $ in Thousands							1 Months Ended				12 Months Ended
	Dec. 06, 2016 shares	Nov. 07, 2016 shares	Oct. 18, 2016 Vote director	Aug. 13, 2014 USD ($) $ / shares shares	Aug. 13, 2014 CNY (¥) shares	Jun. 30, 2014 CNY (¥) shares	Aug. 31, 2016 shares	Aug. 31, 2014 USD ($) shares	Aug. 31, 2014 CNY (¥) shares	Jun. 30, 2014 CNY (¥) shares	Dec. 31, 2016 $ / shares shares	Dec. 31, 2014 CNY (¥)	Dec. 31, 2006 $ / shares shares	Dec. 31, 2015 $ / shares shares	Aug. 13, 2014 ¥ / shares	Dec. 31, 2006 ¥ / shares
Ordinary shares
Par value (in USD or CNY per share) \| $ / shares											$ 0.00005			$ 0.00005
Issuance of ordinary shares in exchange of bonds payable \| ¥												¥ 205,536
Total consideration from repurchased ordinary shares \| ¥												¥ 119,664
Common stock, outstanding shares (in shares)											760,009,043			217,987,922
Ordinary shares issued as preferred stock dividends (in shares)		31,490,164
Restricted shares
Ordinary shares
Granted (in shares)											13,787,480
Restricted shares \| Directors
Ordinary shares
Granted (in shares)							877,400
Ordinary Shares
Ordinary shares
Ordinary shares issued (in shares)													110,000,001
Par value (in USD or CNY per share) \| (per share)													$ 0.00005			¥ 0.000404
Ordinary shares repurchased (in shares)				18,762,292	18,762,292
Ordinary shares repurchased (in USD or CNY per share) \| (per share)				$ 1.0365											¥ 6.3779
Total consideration from repurchased ordinary shares				$ 19,448	¥ 119,664
Number of shares converted		349,087,677
Ordinary Shares \| Bonds due 2015
Ordinary shares
Issuance of ordinary shares in exchange of bonds payable								$ 27,860	¥ 171,431
Conversion to ordinary shares (in shares)								38,397,655	38,397,655
Ordinary Shares \| EDC Holding
Ordinary shares
Ordinary shares issued as part of the consideration to acquire EDC Holding						88,352,558				88,352,558
Fair value of ordinary shares issued as part of the consideration to acquire EDC Holding \| ¥						¥ 472,945				¥ 472,945
Series C
Ordinary shares
Conversion to ordinary shares (in shares)											(238,526,241)
Minimum holding of issued share capital				40.00%	40.00%
Series C \| Bonds due 2015
Ordinary shares
Issuance of ordinary shares in exchange of bonds payable								$ 27,860	¥ 171,431
ADS \| IPO
Ordinary shares
Ordinary shares issued (in shares)		19,250,000
ADS \| Over-Allotment Option
Ordinary shares
Ordinary shares issued (in shares)	820,735
Class A
Ordinary shares
Number of votes per share at general meetings \| Vote			1
Common stock, outstanding shares (in shares)		692,418,707
Number of ADS per Class A ordinary share	8
Ordinary shares issued as preferred stock dividends (in shares)		31,490,164
Class A \| IPO
Ordinary shares
Ordinary shares issued (in shares)		154,000,000
Class A \| Over-Allotment Option
Ordinary shares
Ordinary shares issued (in shares)	6,565,880
Class B
Ordinary shares
Number of votes per share at general meetings \| Vote			1
Number of votes per share regarding certain matters in general meetings \| Vote			20
Number of directors for simple majority \| director			6
Right to nominate, number of directors \| director			5
Common stock, outstanding shares (in shares)		67,590,336
Redeemable preferred shares
Ordinary shares
Conversion to ordinary shares (in shares)											(349,087,677)
Number of shares converted		(349,087,677)
Conversion ratio of preferred shares to ordinary share		1												1
Redeemable preferred shares \| EDC Holding
Ordinary shares
Ordinary shares issued as part of the consideration to acquire EDC Holding						110,810,606

SHARE-BASED COMPENSATION - Plans and Grants (Details)	1 Months Ended						12 Months Ended
SHARE-BASED COMPENSATION - Plans and Grants (Details)	May 31, 2016 $ / shares shares	May 31, 2016 ¥ / shares shares	Jan. 31, 2015 installment $ / shares shares	Jan. 31, 2015 installment ¥ / shares shares	Jul. 31, 2014 $ / shares shares	Jul. 31, 2014 ¥ / shares shares	Dec. 31, 2016 ¥ / shares shares	Dec. 31, 2015 ¥ / shares shares	Dec. 31, 2014 ¥ / shares shares	Aug. 31, 2016 shares
SHARE-BASED COMPENSATION
Share options granted (in shares)							11,551,507	519,271	17,642,130
Exercise price (in USD or CNY per share) \| ¥ / shares							¥ 5.2	¥ 4.8	¥ 4.8
External consultants
SHARE-BASED COMPENSATION
Unvested options (in shares)							600,000	1,066,667
Share options \| External consultants
SHARE-BASED COMPENSATION
Exercise price (in USD or CNY per share) \| (per share)					$ 0.7792	¥ 4.8
Contractual term					5 years	5 years
Share options \| External Consultants granted 4,158,315 options
SHARE-BASED COMPENSATION
Share options granted (in shares)					4,158,315	4,158,315
Share options \| A Consultant granted 1,275,000 options
SHARE-BASED COMPENSATION
Share options granted (in shares)					1,275,000	1,275,000
Share options \| External Consultants granted 400,000 options
SHARE-BASED COMPENSATION
Share options granted (in shares)					400,000	400,000
Unvested options (in shares)							266,666	400,000
Share options \| A Consultant granted 1,000,000 options
SHARE-BASED COMPENSATION
Share options granted (in shares)			1,000,000	1,000,000
Exercise price (in USD or CNY per share) \| (per share)			$ 0.7792	¥ 4.8
Contractual term			5 years	5 years
Unvested options (in shares)							333,334	666,667
Installment period in each installment			6 months	6 months
Number of installments \| installment			6	6
Share options \| Tranche one \| A Consultant granted 1,275,000 options
SHARE-BASED COMPENSATION
Vesting period					0 days	0 days
Vesting percentage					75.00%	75.00%
Shares vested (in shares)					956,250	956,250
Share options \| Tranche one \| External Consultants granted 400,000 options
SHARE-BASED COMPENSATION
Vesting percentage					33.33%	33.33%
Share options \| Tranche two \| A Consultant granted 1,275,000 options
SHARE-BASED COMPENSATION
Share options granted (in shares)					318,750	318,750
Vesting period					11 months	11 months
Share options \| Tranche two \| External Consultants granted 400,000 options
SHARE-BASED COMPENSATION
Vesting percentage					33.33%	33.33%
Share options \| Tranche three \| External Consultants granted 400,000 options
SHARE-BASED COMPENSATION
Vesting percentage					33.33%	33.33%
Employees, officers and directors \| Share options
SHARE-BASED COMPENSATION
Share options granted (in shares)	11,084,840	11,084,840			12,394,753	12,394,753
Exercise price (in USD or CNY per share) \| (per share)	$ 0.7792	¥ 5.0328			$ 0.7792	¥ 4.7943
Contractual term	5 years	5 years
Employees, officers and directors \| Share options \| Vesting Schedule One \| Tranche one
SHARE-BASED COMPENSATION
Vesting period					0 days	0 days
Vesting percentage					63.00%	63.00%
Employees, officers and directors \| Share options \| Vesting Schedule One \| Tranche two
SHARE-BASED COMPENSATION
Vesting period					48 months	48 months
Shares that vest each month (as a percent)					2.00%	2.00%
Employees, officers and directors \| Share options \| Vesting Schedule Two \| Tranche one
SHARE-BASED COMPENSATION
Vesting period					0 days	0 days
Vesting percentage					71.00%	71.00%
Employees, officers and directors \| Share options \| Vesting Schedule Two \| Tranche two
SHARE-BASED COMPENSATION
Vesting period					48 months	48 months
Shares that vest each month (as a percent)					2.00%	2.00%
Employees, officers and directors \| Share options \| Vesting Schedule Three \| Tranche one
SHARE-BASED COMPENSATION
Vesting period					0 days	0 days
Vesting percentage					75.00%	75.00%
Employees, officers and directors \| Share options \| Vesting Schedule Three \| Tranche two
SHARE-BASED COMPENSATION
Vesting period					48 months	48 months
Shares that vest each month (as a percent)					2.00%	2.00%
Employees, officers and directors \| Share options \| Vesting Schedule Four \| Tranche one
SHARE-BASED COMPENSATION
Vesting period					0 days	0 days
Vesting percentage					95.00%	95.00%
Employees, officers and directors \| Share options \| Vesting Schedule Four \| Tranche two
SHARE-BASED COMPENSATION
Vesting period					40 months	40 months
Shares that vest each month (as a percent)					2.50%	2.50%
Employees, officers and directors \| Share options \| Maximum
SHARE-BASED COMPENSATION
Contractual term					6 years	6 years
Employees, officers and directors \| Share options \| Minimum
SHARE-BASED COMPENSATION
Contractual term					5 years	5 years
The 2014 Plan
SHARE-BASED COMPENSATION
Total number shares which may be issued					29,240,000	29,240,000
The 2016 Plan
SHARE-BASED COMPENSATION
Total number shares which may be issued										56,707,560

SHARE-BASED COMPENSATION - Stock Option Activity (Details) - ¥ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Number of options
Outstanding, beginning (in shares)	17,193,534	17,463,207
Granted (in shares)	11,551,507	519,271	17,642,130
Forfeited	(155,259)	(788,944)	(178,923)
Outstanding, ending (in shares)	28,589,782	17,193,534	17,463,207
Weighted average exercise price
Outstanding, beginning (in RNB per share)	¥ 4.8
Granted (in RMB per share)	5.2	¥ 4.8	¥ 4.8
Forfeited (in RMB per share)	4.8	4.8	4.8
Outstanding, ending (in RMB per share)	5.2	4.8
Weighted average grant-date fair value per option
Outstanding, beginning (in RMB per share)	1.9
Granted (in RMB per share)	4.9	1.9	1.9
Forfeited (in RMB per share)	1.9	1.9	¥ 1.9
Outstanding, ending (in RMB per share)	¥ 3.2	¥ 1.9
Options vested and expect to vest
Number of options	28,589,782
Weighted average exercise price (in RMB per share)	¥ 5.2
Weighted average grant-date fair value per option (in RMB per share)	¥ 3.2
Stock options outstanding and stock options exercisable
Number of shares	28,589,782
Weighted average remaining contractual life (years)	3 years 2 months 12 days
Weighted average exercise price (in RMB per share)	¥ 5.2
External consultants
Other disclosures
Forfeitable and unvested (in shares)	600,000	1,066,667
Employee stock options
Other disclosures
Forfeitable and unvested (in shares)	0

SHARE-BASED COMPENSATION - Fair Value Assumptions - Stock Options (Details) - Share options	1 Months Ended
	May 31, 2016 $ / shares	Jan. 31, 2015 $ / shares	Jul. 31, 2014 $ / shares	May 31, 2016 ¥ / shares	Jan. 31, 2015 ¥ / shares	Jul. 31, 2014 ¥ / shares
Fair value assumptions
Risk-free rate of return (as a percent)	1.98%	2.27%	2.25%
Volatility (as a percent)	28.50%	29.80%	31.40%
Exercise multiple	2.2	2.2	2.2
Fair value of underlying ordinary share \| (per share)	$ 1.51	$ 0.90	$ 0.88	¥ 9.8	¥ 5.5	¥ 5.35
Expected term	5 years	5 years
Maximum
Fair value assumptions
Expected term			6 years
Minimum
Fair value assumptions
Expected term			5 years

SHARE-BASED COMPENSATION - Settlement of Liability Classified Restricted Shares (Details) - CNY (¥) ¥ in Thousands	1 Months Ended		12 Months Ended
	Aug. 31, 2016	May 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
SHARE-BASED COMPENSATION
Compensation expense			¥ 64,165	¥ 4,061	¥ 27,333
Directors
SHARE-BASED COMPENSATION
Liability to settle		¥ 11,733
Liability to settle in cash		4,194
Liability to settle in shares		7,539
Compensation expense		¥ 11,733
Liability paid in cash	¥ 4,194
Restricted shares
SHARE-BASED COMPENSATION
Compensation expense			¥ 4,697
Granted (in shares)			13,787,480
Restricted shares \| Directors
SHARE-BASED COMPENSATION
Granted (in shares)	877,400
Percentage of shares restricted to sale or otherwise disposal	50.00%
Period of restriction on sale or otherwise disposal	1 year

SHARE-BASED COMPENSATION - Restricted Stock Activity (Details) - CNY (¥) ¥ / shares in Units, ¥ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Weighted average grant-date fair value per share (RMB)
Total share based compensation expense		¥ 64,165	¥ 4,061	¥ 27,333
Restricted shares
Number of Shares
Granted (in shares)		13,787,480
Vested (in shares)		(877,400)
Outstanding, end	12,910,080	12,910,080
Weighted average grant-date fair value per share (RMB)
Granted (in RMB per share)		¥ 6.1
Vested (in RMB per share)		(8.6)
Outstanding, end	¥ 6.0	¥ 6.0
Total share based compensation expense		¥ 4,697
Total unrecognized compensation expense	¥ 72,720	¥ 72,720
Weighted average period over which unrecognized compensation expense is expected to be recognized		2 years 1 month 6 days
Restricted shares \| Employees, officers and directors
Number of Shares
Granted (in shares)	12,910,080

SHARE-BASED COMPENSATION - Fair Value Assumptions - Restricted Shares (Details) - 12 months ended Dec. 31, 2016 - Restricted shares	$ / shares	¥ / shares
Fair value assumptions
Share price at grant date \| (per share)	$ 1.24	¥ 8.60
Maximum
Fair value assumptions
Risk-free rate of return (as a percent)	1.65%
Volatility (as a percent)	24.80%
Expected term	5 years
Minimum
Fair value assumptions
Risk-free rate of return (as a percent)	0.68%
Volatility (as a percent)	22.35%
Expected term	1 year

SHARE-BASED COMPENSATION - Expenses (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
SHARE-BASED COMPENSATION
Compensation expense	¥ 64,165	¥ 4,061	¥ 27,333
Cost of revenue
SHARE-BASED COMPENSATION
Compensation expense	2,114	484	2,851
Selling and marketing expenses
SHARE-BASED COMPENSATION
Compensation expense	6,590	325	1,957
General and administrative expenses
SHARE-BASED COMPENSATION
Compensation expense	55,409	¥ 3,252	¥ 22,525
Research and development expenses
SHARE-BASED COMPENSATION
Compensation expense	¥ 52

REVENUE (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
REVENUE (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net revenue
Service revenue	¥ 1,003,015	¥ 653,591	¥ 450,940
Equipment sales	52,945	50,045	17,397
Net revenue	¥ 1,055,960	¥ 703,636	¥ 468,337

INCOME TAX - Tax rate (Details)	12 Months Ended
INCOME TAX - Tax rate (Details)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
INCOME TAX
Income tax rate (as a percent)	25.00%	25.00%	25.00%
PRC
INCOME TAX
Income tax rate (as a percent)	25.00%
Hong Kong
INCOME TAX
Income tax rate (as a percent)	16.50%

INCOME TAX - By tax Jurisdictions (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loss before income taxes:
PRC	¥ 144,158	¥ 94,190	¥ 112,572
Other jurisdictions	140,569	16,377	22,010
Total loss before income taxes	284,727	110,567	134,582
Current tax expenses:
PRC	311	(1,650)	436
Other jurisdictions	1,998	256	5
Total current tax expenses(benefits)	2,309	(1,394)	441
Deferred tax benefits:
PRC	(10,935)	(10,589)	(4,877)
Other jurisdictions	311		(147)
Total deferred tax benefits	(10,624)	(10,589)	(5,024)
Total income taxes benefits	¥ (8,315)	¥ (11,983)	¥ (4,583)

INCOME TAX - Reconciliation of statutory tax rate and effective tax rate (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of the differences between actual income tax expense and the PRC statutory tax rate
PRC enterprise income tax rate (as a percent)	25.00%	25.00%	25.00%
Non-PRC entities not subject to income tax (as a percent)	(13.70%)	(3.80%)	(1.80%)
Tax differential for entities in non-PRC jurisdiction (as a percent)	0.50%	0.00%	(0.80%)
Tax effect of permanent differences (as a percent)	(0.30%)	(0.60%)	(0.40%)
Change in valuation allowance (as a percent)	(8.40%)	(9.40%)	(18.40%)
Return to provision adjustment	(0.20%)	(0.40%)	(0.20%)
Effective tax rate (as a percent)	2.90%	10.80%	3.40%

INCOME TAX - Deferred tax assets and liabilities (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Bad debt provision		¥ 539
Government subsidy	¥ 3,763	4,067
Accrued expenses	23,324	8,732
Asset retirement obligation	2,377	1,444
Net operating loss carry forwards	141,749	135,878
Total gross deferred tax assets	171,213	150,660
Valuation allowance on deferred tax assets	(134,935)	(118,952)	¥ (116,403)	¥ (117,065)
Deferred tax assets, net of valuation allowance	36,278	31,708
Deferred tax liabilities:
Property and equipment	(36,644)	(37,982)
Intangible assets	(22,914)	(11,430)
Prepaid land use rights	(1,733)	(1,774)
Obligation under capital lease and other financing obligations	(15,641)	(10,657)
Total deferred tax liabilities	(76,932)	(61,843)
Net deferred tax liabilities	(40,654)	(30,135)
Analysis as:
Current deferred tax assets (note 4)		5,193
Non-current deferred tax assets	12,626	2,363
Non-current deferred tax liabilities	(53,280)	(37,691)
Net deferred tax liabilities	¥ (40,654)	¥ (30,135)

INCOME TAX - Movement of the valuation allowance (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement of the valuation allowance
Balance at the beginning of the year	¥ 118,952	¥ 116,403	¥ 117,065
(Decrease) increase during the year	15,983	2,549	(662)
Balance at the end of the year	¥ 134,935	¥ 118,952	¥ 116,403

INCOME TAX - Net operating losses (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating losses carry forwards
PRC enterprise income tax rate (as a percent)	25.00%	25.00%	25.00%
State administration of taxation, China
Operating losses carry forwards
Net operating losses carry forwards	¥ 493,057
Net operating losses carry forwards expire if unused by December 31, 2017	32,405
Net operating losses carry forwards expire if unused by December 31, 2018	64,427
Net operating losses carry forwards expire if unused by December 31, 2019	222,900
Net operating losses carry forwards expire if unused by December 31, 2020	60,137
Net operating losses carry forwards expire if unused by December 31, 2021	¥ 113,188
PRC enterprise income tax rate (as a percent)	25.00%
Withholding tax for dividends distributed by a PRC-resident enterprise to its non-PRC-resident corporate investor (as a percent)	10.00%

DISTRIBUTION OF PROFIT (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
DISTRIBUTION OF PROFIT (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
DISTRIBUTION OF PROFIT
Percentage of after-tax profits required to be appropriated to general reserve fund	10.00%
General reserve as a percentage of registered capital up to which after-tax profit of PRC subsidiaries and VIEs could discontinue allocations to the general reserve fund	50.00%
Aggregate amounts of capital and statutory reserves restricted	¥ 1,975,175	¥ 1,323,122
Amount of non-distributable general reserve fund	¥ 0	¥ 0

LOSS PER ORDINARY SHARE - Computation of basic and diluted loss per share (Details) ¥ / shares in Units, ¥ in Thousands, $ in Thousands			12 Months Ended
	Nov. 07, 2016 USD ($)	Nov. 07, 2016 CNY (¥)	Dec. 31, 2016 CNY (¥) ¥ / shares shares	Dec. 31, 2015 CNY (¥) ¥ / shares shares	Dec. 31, 2014 CNY (¥) ¥ / shares shares
Computation of basic and diluted loss per share
Net loss			¥ 276,412	¥ 98,584	¥ 129,999
Extinguishment of redeemable preferred shares upon repurchase and exchange					106,515
Change in redemption value of redeemable preferred shares			(205,670)	110,926	69,116
(Cumulative) Dividend on preferred shares			332,660	7,127	3,509
Net loss attributable to ordinary shareholders			¥ 403,402	¥ 216,637	¥ 309,139
Weighted average number of ordinary shares outstanding-basic and diluted \| shares			299,093,937	217,987,922	162,070,745
Loss per ordinary share - basic and diluted \| ¥ / shares			¥ (1.35)	¥ (0.99)	¥ (1.91)
Conversion of preferred shares to ordinary shares			¥ 97,274
Dividends on redeemable preferred shares			302,944
Preference dividends	$ 50,812	¥ 343,296	¥ 343,296

LOSS PER ORDINARY SHARE - Excluded from the computation of diluted loss per share (Details) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive securities excluded from computation of earnings per share
Total	135,477,699	425,973,367	366,550,884
Share options/restricted shares
Antidilutive securities excluded from computation of earnings per share
Total	41,499,862	17,193,534	17,463,207
Convertible bonds payable
Antidilutive securities excluded from computation of earnings per share
Total	93,977,837	59,692,156
Redeemable preferred shares
Antidilutive securities excluded from computation of earnings per share
Total		349,087,677	349,087,677

SEGMENT INFORMATION (Details)	12 Months Ended
SEGMENT INFORMATION (Details)	Dec. 31, 2016 segment
SEGMENT INFORMATION
Number of operating segments	1

MAJOR CUSTOMERS (Details) ¥ in Thousands	12 Months Ended
MAJOR CUSTOMERS (Details) ¥ in Thousands	Dec. 31, 2016 CNY (¥) customer	Dec. 31, 2015 CNY (¥) customer	Dec. 31, 2014 CNY (¥) customer
MAJOR CUSTOMERS
Revenue	¥ 1,055,960	¥ 703,636	¥ 468,337
Revenue \| Customer concentration
MAJOR CUSTOMERS
Number of customers generated over 10% of the Company's total revenues \| customer	2	1	1
Revenue \| Customer concentration \| Customer A
MAJOR CUSTOMERS
Revenue	¥ 169,052	¥ 141,711	¥ 125,687
Revenue \| Customer concentration \| Customer B
MAJOR CUSTOMERS
Revenue	¥ 153,863

COMMITMENTS - Capital commitments (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015
COMMITMENTS
Capital commitments outstanding not provided for in the financial statements, Contracted for	¥ 510,999	¥ 272,958

COMMITMENTS - Lease commitments (Details) ¥ in Thousands	Dec. 31, 2016 CNY (¥)
Operating lease commitments
2017	¥ 124,293
2018	98,566
2019	75,657
2020	57,268
2021	36,822
Total	¥ 838,213

RELATED PARTY TRANSACTIONS - Major transactions with related parties (Details) ¥ in Thousands, $ in Thousands			1 Months Ended		6 Months Ended	12 Months Ended
	Nov. 07, 2016 USD ($)	Nov. 07, 2016 CNY (¥)	Aug. 31, 2014 USD ($)	Aug. 31, 2014 CNY (¥)	Jun. 30, 2014 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 CNY (¥)	Dec. 31, 2014 CNY (¥)
RELATED PARTY TRANSACTIONS
Interest income									¥ 4,296
Repurchase of redeemable preferred shares									273,562
Preference dividends	$ 50,812	¥ 343,296				¥ 343,296
Loan from a related party								¥ 64,936
Repayment of a related party loan						65,474
Convertible bonds from a related party						327,580
Interest expenses						32,245		2,579	244
Affiliated Entity
RELATED PARTY TRANSACTIONS
Preference dividends						343,296
EDC Holding
RELATED PARTY TRANSACTIONS
Service fees charged by EDC Holding									55,869
Loans made to EDC Holding									307,048
Interest income					¥ 4,296
Interest expenses					¥ 244				¥ 244
STT GDC Pte. Ltd.
RELATED PARTY TRANSACTIONS
Preference dividends						223,225
Interest expenses						32,245	$ 397	¥ 2,579
SBCVC
RELATED PARTY TRANSACTIONS
Repurchase of redeemable preferred shares			$ 44,458	¥ 273,562
Preference dividends						109,665
Other non-principal preferred shareholders
RELATED PARTY TRANSACTIONS
Preference dividends						¥ 10,406

RELATED PARTY TRANSACTIONS - Balances with related parties (Details) ¥ / shares in Units, $ / shares in Units, ¥ in Thousands, $ in Thousands					1 Months Ended			6 Months Ended	12 Months Ended
	Nov. 07, 2016 USD ($) $ / shares shares	Nov. 07, 2016 CNY (¥) shares	Jan. 29, 2016 USD ($)	Jan. 29, 2016 CNY (¥)	Aug. 31, 2014 USD ($) $ / shares shares	Aug. 31, 2014 CNY (¥) shares	Dec. 31, 2013 CNY (¥)	Jun. 30, 2014 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 CNY (¥)	Dec. 31, 2014 CNY (¥)	Jan. 29, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)	Aug. 31, 2014 ¥ / shares	Aug. 13, 2014 $ / shares	Aug. 13, 2014 ¥ / shares	Jan. 31, 2013 USD ($)	Jan. 31, 2013 CNY (¥)
RELATED PARTY TRANSACTIONS
Amount due to														¥ 67,604
Interest income												¥ 4,296
Interest expenses									¥ 32,245		¥ 2,579	244
Repurchase of redeemable preferred shares												273,562
Preference dividend (note 15)	$ 50,812	¥ 343,296							343,296
Preference dividend paid in cash	11,449	76,502
Issuance of ordinary shares to settle preference dividend	$ 39,363	¥ 266,794							266,794
Ordinary shares issued as preferred stock dividends (in shares) \| shares	31,490,164	31,490,164
Loan received from a related party											64,936
Outstanding short-term loan repaid by a loan from related party									65,474
Outstanding short-term borrowings									239,777					333,000
ADS
RELATED PARTY TRANSACTIONS
Initial public offering price (dollar per share) \| $ / shares	$ 10.00
Ordinary Shares
RELATED PARTY TRANSACTIONS
Repurchased price per share \| (per share)																$ 1.0365	¥ 6.3779
Initial public offering price (dollar per share) \| $ / shares	$ 1.25
Affiliated Entity
RELATED PARTY TRANSACTIONS
Preference dividend (note 15)									343,296
SBCVC
RELATED PARTY TRANSACTIONS
Amount due to												23,300
Repurchased price per share \| (per share)					$ 1.0365										¥ 6.3779
Repurchase of redeemable preferred shares					$ 44,458	¥ 273,562
Preference dividend (note 15)									109,665
SBCVC \| Series A
RELATED PARTY TRANSACTIONS
Repurchase of redeemable preferred shares (in share) \| shares					13,905,901	13,905,901
SBCVC \| Series A*
RELATED PARTY TRANSACTIONS
Repurchase of redeemable preferred shares (in share) \| shares					4,403,119	4,403,119
SBCVC \| Series B
RELATED PARTY TRANSACTIONS
Repurchase of redeemable preferred shares (in share) \| shares					1,640,183	1,640,183
SBCVC \| Series B1
RELATED PARTY TRANSACTIONS
Repurchase of redeemable preferred shares (in share) \| shares					7,338,532	7,338,532
SBCVC \| Series B2
RELATED PARTY TRANSACTIONS
Repurchase of redeemable preferred shares (in share) \| shares					6,643,303	6,643,303
SBCVC \| Series B4
RELATED PARTY TRANSACTIONS
Repurchase of redeemable preferred shares (in share) \| shares					8,961,143	8,961,143
STT GDC Pte. Ltd.
RELATED PARTY TRANSACTIONS
Amount due to														67,604
Interest expenses									32,245	$ 397	¥ 2,579
Preference dividend (note 15)									¥ 223,225
Short-term loan										10,000				64,936
Accrued loan interest										$ 397				¥ 2,668
Loan received from a related party			$ 50,000	¥ 327,580
Outstanding short-term loan repaid by a loan from related party			10,000	¥ 65,474
Outstanding short-term borrowings			$ 10,000										¥ 65,474
EDC Holding
RELATED PARTY TRANSACTIONS
Loans made to EDC Holding								¥ 307,048
Interest income								4,296
Loan from a related party																		$ 8,000	¥ 49,222
Interest expenses								244				¥ 244
EDC Holding \| Service agreement
RELATED PARTY TRANSACTIONS
Prepayment for service from related party							¥ 320,000
Service period							2 years
Services received								¥ 55,869

PARENT ONLY FINANCIAL INFORMATION - Condensed Balance Sheets (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets
Cash	¥ 1,811,319	¥ 924,498
Prepaid expenses	50,361	51,395
Total current assets	2,210,313	1,186,699
Other non-current assets	98,725	57,516
Total assets	8,203,866	5,128,272
Current liabilities
Accrued expenses and other payables	207,950	118,316
Due to a related party		67,604
Total current liabilities	1,479,221	925,049
Convertible bonds payable	1,040,550	648,515
Other long-term liabilities	111,706	79,005
Total liabilities	5,217,392	3,073,463
Redeemable preferred shares (US$0.00005 par value; 350,563,436 shares authorized; 349,087,677 shares issued and outstanding with aggregate redemption amount of RMB2,277,059 as of December 31, 2015)		2,395,314
Shareholders' equity (deficit)
Ordinary shares (US$0.00005 par value; 675,636,564 and 2,002,000,000 shares authorized; 217,987,922 and 760,009,043 shares issued and outstanding as of December 31, 2015 and 2016, respectively))	260	76
Additional paid-in capital	4,036,959	303,621
Accumulated other comprehensive loss	(192,080)	(61,949)
Accumulated deficit	(858,665)	(582,253)
Total shareholders' equity (deficit)	2,986,474	(340,505)	¥ (16,565)	¥ (301,199)
Total liabilities, redeemable preferred shares and shareholders' equity (deficit)	8,203,866	5,128,272
Parent Company
Current assets
Cash	1,030,627	643,926
Prepaid expenses	1,011
Total current assets	1,031,638	643,926
Investment and loans to subsidiaries	3,054,835	2,152,027
Other non-current assets	15,856
Total assets	4,102,329	2,795,953
Current liabilities
Accrued expenses and other payables	23,266	3,782
Due to subsidiaries	927	20,890
Due to a related party		67,604
Total current liabilities	24,193	92,276
Convertible bonds payable	1,040,550	648,515
Other long-term liabilities	51,112	353
Total liabilities	1,115,855	741,144
Redeemable preferred shares (US$0.00005 par value; 350,563,436 shares authorized; 349,087,677 shares issued and outstanding with aggregate redemption amount of RMB2,277,059 as of December 31, 2015)		2,395,314
Shareholders' equity (deficit)
Ordinary shares (US$0.00005 par value; 675,636,564 and 2,002,000,000 shares authorized; 217,987,922 and 760,009,043 shares issued and outstanding as of December 31, 2015 and 2016, respectively))	260	76
Additional paid-in capital	4,036,959	303,621
Accumulated other comprehensive loss	(192,080)	(61,949)
Accumulated deficit	(858,665)	(582,253)
Total shareholders' equity (deficit)	2,986,474	(340,505)
Commitments and contingencies
Total liabilities, redeemable preferred shares and shareholders' equity (deficit)	¥ 4,102,329	¥ 2,795,953

PARENT ONLY FINANCIAL INFORMATION - Condensed Balance Sheets (Parenthetical) (Details) ¥ in Thousands	Dec. 31, 2016 $ / shares shares	Dec. 31, 2015 $ / shares	Dec. 31, 2015 CNY (¥) shares
Condensed Balance Sheets
Redeemable preferred shares, par value (in dollars per share) \| $ / shares		$ 0.00005
Redeemable preferred shares, authorized			350,563,436
Redeemable preferred shares, issued			349,087,677
Redeemable preferred shares, outstanding			349,087,677
Redeemable preferred shares, aggregate redemption amount \| ¥			¥ 2,277,059
Ordinary shares, par value (in dollars per share) \| $ / shares	$ 0.00005	0.00005
Ordinary shares, shares authorized	2,002,000,000		675,636,564
Ordinary shares, shares issued	760,009,043		217,987,922
Ordinary shares, shares outstanding	760,009,043		217,987,922
Parent Company
Condensed Balance Sheets
Redeemable preferred shares, par value (in dollars per share) \| $ / shares		0.00005
Redeemable preferred shares, authorized			350,563,436
Redeemable preferred shares, issued			349,087,677
Redeemable preferred shares, outstanding			349,087,677
Redeemable preferred shares, aggregate redemption amount \| ¥			¥ 2,277,059
Ordinary shares, par value (in dollars per share) \| $ / shares	$ 0.00005	$ 0.00005
Ordinary shares, shares authorized	2,002,000,000		675,636,564
Ordinary shares, shares issued	760,009,043		217,987,922
Ordinary shares, shares outstanding	760,009,043		217,987,922

PARENT ONLY FINANCIAL INFORMATION - Condensed Statements of Operations (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Statements of Operations
Net revenue	¥ 1,055,960	¥ 703,636	¥ 468,337
Cost of revenue	(790,286)	(514,997)	(388,171)
Gross profit	265,674	188,639	80,166
Operating expenses
Selling and marketing expenses	(71,578)	(57,588)	(40,556)
General and administrative expenses	(227,370)	(128,714)	(113,711)
Research and development expenses	(9,100)	(3,554)	(1,597)
Loss from operations	(42,374)	(1,217)	(75,698)
Other income (expenses):
Interest income	2,070	1,355	6,935
Interest expenses	(265,234)	(126,901)	(131,908)
Gain on remeasurement of equity investment			62,506
Others, net	284	1,174	(412)
Loss before income taxes	(284,727)	(110,567)	(134,582)
Income tax expenses	8,315	11,983	4,583
Net loss	(276,412)	(98,584)	(129,999)
Parent Company
Condensed Statements of Operations
Cost of revenue	(2,381)
Gross profit	(2,381)
Operating expenses
Selling and marketing expenses	(8,914)	(1,566)	(2,387)
General and administrative expenses	(82,794)	(14,665)	(32,166)
Research and development expenses	(52)
Loss from operations	(94,141)	(16,231)	(34,553)
Other income (expenses):
Interest income	16		80
Interest expenses	(97,603)	(3,297)	(35,192)
Gain on remeasurement of equity investment			62,506
Equity in loss of subsidiaries	(84,952)	(79,056)	(122,742)
Others, net	268		(98)
Loss before income taxes	(276,412)	(98,584)	(129,999)
Net loss	¥ (276,412)	¥ (98,584)	¥ (129,999)

PARENT ONLY FINANCIAL INFORMATION - Condensed Statements of Comprehensive Loss (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Statements of Comprehensive Loss
Net loss	¥ (276,412)	¥ (98,584)	¥ (129,999)
Other comprehensive income (loss)
Foreign currency translation adjustments, net of nil tax	(130,131)	(118,491)	4,114
Comprehensive loss	(406,543)	(217,075)	(125,885)
Parent Company
Condensed Statements of Comprehensive Loss
Net loss	(276,412)	(98,584)	(129,999)
Other comprehensive income (loss)
Foreign currency translation adjustments, net of nil tax	(130,131)	(118,491)	4,114
Comprehensive loss	¥ (406,543)	¥ (217,075)	¥ (125,885)

PARENT ONLY FINANCIAL INFORMATION - Condensed Statements of Comprehensive Loss (Parenthetical) (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Statements of Comprehensive Loss
Foreign currency translation adjustments, tax	¥ 0	¥ 0	¥ 0
Parent Company
Condensed Statements of Comprehensive Loss
Foreign currency translation adjustments, tax	¥ 0	¥ 0	¥ 0

PARENT ONLY FINANCIAL INFORMATION - Condensed Statements of Cash Flows (Details) ¥ in Thousands, $ in Thousands			12 Months Ended
	Nov. 07, 2016 USD ($)	Nov. 07, 2016 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)	Dec. 31, 2014 CNY (¥)
Operating activities:
Net cash provided by (used in) operating activities			¥ (150,228)	¥ (80,298)	¥ 27,937
Investing activities:
Deposit paid for a potential acquisition			(15,000)
Net cash used in investing activities			(1,147,064)	(731,905)	(523,749)
Financing activities:
Proceeds from issuance of convertible bonds			327,580	648,950
Proceeds from issuance of bonds payable					114,950
Repayment of bonds payable				(14,330)	(4,081)
Proceeds from a related party loan				64,936
Repayment of a related party loan			(65,474)
Proceeds from issuance of Series C redeemable preferred shares					1,521,295
Payment of issuance costs of Series C redeemable preferred shares					(20,128)
Net proceeds from issuance of ordinary shares for initial public offering			1,221,518
Payment of preferred shares dividends			(76,502)
Repurchase of ordinary shares					(119,664)
Repurchase of redeemable preferred shares				(23,300)	(455,366)
Net cash provided by financing activities			2,128,614	1,127,685	1,056,287
Effect of exchange rate changes on cash			55,499	2,258	(2,328)
Net increase in cash			886,821	317,740	558,147
Cash at beginning of year			924,498	606,758	48,611
Cash at end of year			1,811,319	924,498	606,758
Supplemental disclosures of cash flow information
Interest paid			228,678	81,216	55,149
Supplemental disclosures of non-cash investing and financing activities
Issuance of ordinary shares to settle preference dividend	$ 39,363	¥ 266,794	266,794
Issuance of ordinary shares in exchange of bonds payable					205,536
Issuance of ordinary and preferred shares for the acquisition of EDC Holding					1,184,242
Parent Company
Operating activities:
Net cash provided by (used in) operating activities			(62,591)	(4,895)	(6,609)
Investing activities:
Investment in a subsidiary					(92,300)
Deposit paid for a potential acquisition			(15,000)
Increase of due from subsidiaries			(990,617)	(93,101)	(925,539)
Net cash used in investing activities			(1,005,617)	(93,101)	(1,017,839)
Financing activities:
Proceeds from issuance of convertible bonds			327,580	648,950
Proceeds from issuance of bonds payable					114,950
Repayment of bonds payable				(14,330)	(4,081)
Proceeds from a related party loan				64,936
Repayment of a related party loan			(65,474)
Proceeds from issuance of Series C redeemable preferred shares					1,521,295
Payment of issuance costs of Series C redeemable preferred shares					(20,128)
Net proceeds from issuance of ordinary shares for initial public offering			1,221,518
Payment of preferred shares dividends			(76,502)
Repurchase of ordinary shares					(119,664)
Repurchase of redeemable preferred shares				(23,300)	(455,366)
Net cash provided by financing activities			1,407,122	676,256	1,037,006
Effect of exchange rate changes on cash			47,787	57,565	(4,459)
Net increase in cash			386,701	635,825	8,099
Cash at beginning of year			643,926	8,101	2
Cash at end of year			1,030,627	643,926	8,101
Supplemental disclosures of cash flow information
Interest paid			45,495	¥ 3,463	1,317
Supplemental disclosures of non-cash investing and financing activities
Issuance of ordinary shares to settle preference dividend			¥ 266,794
Issuance of ordinary shares in exchange of bonds payable					205,536
Issuance of ordinary and preferred shares for the acquisition of EDC Holding					¥ 1,184,242

SUBSEQUENT EVENTS (Details) - Subsequent Events ¥ in Thousands, $ in Thousands	Apr. 10, 2017 USD ($)	Apr. 10, 2017 CNY (¥)	Mar. 30, 2017 USD ($) subsidiary	Mar. 16, 2017 CNY (¥)	Mar. 15, 2017 USD ($)	Mar. 15, 2017 CNY (¥)	Mar. 30, 2017 CNY (¥) subsidiary
Service agreement \| Colocation services
SUBSEQUENT EVENTS
Termination fees received					$ 6,742	¥ 46,769
Data center project in Shenzhen, China (Shenzhen 5)
SUBSEQUENT EVENTS
Aggregate purchase price				¥ 313,000
Contingent consideration				¥ 312,000
Two Subsidiaries, C \| Facility Agreement with a third party bank
SUBSEQUENT EVENTS
Number of subsidiaries entered into loan facilities \| subsidiary			2				2
Principal amount of credit facility			$ 45,000				¥ 310,700
Loan drew down	$ 45,000	¥ 310,700
Effective interest rate (as a percent)			5.41%