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Document and Entity Information	12 Months Ended
Document and Entity Information	Dec. 31, 2017 shares
Entity Registrant Name	GDS Holdings Ltd
Entity Central Index Key	0001526125
Document Type	20-F
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Class A
Entity Common Stock, Shares Outstanding	873,679,343
Class B
Entity Common Stock, Shares Outstanding	67,590,336

CONSOLIDATED BALANCE SHEETS - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current assets
Cash (including cash of VIEs of RMB397,948 and RMB266,560 as of December 31, 2016 and 2017, respectively)	¥ 1,873,446	¥ 1,811,319
Restricted cash (including restricted cash of VIEs of RMB10,091 and RMB10,837 as of December 31, 2016 and 2017, respectively)	10,837	27,673
Accounts receivable, net of allowance for doubtful accounts (including accounts receivable, net of allowance for doubtful accounts, of VIEs of RMB172,538 and RMB348,536 as of December 31, 2016 and 2017, respectively)	364,654	198,851
Value-added-tax ("VAT") recoverable (including VAT recoverable of VIEs of RMB13,399 and RMB27,596 as of December 31, 2016 and 2017, respectively)	112,067	72,958
Prepaid expenses (including prepaid expenses of VIEs of RMB28,466 and RMB32,919 as of December 31, 2016 and 2017, respectively)	50,373	50,361
Other current assets (including other current asset of VIEs of RMB1,201 and RMB7,283 as of December 31, 2016 and 2017, respectively)	42,651	49,151
Total current assets	2,454,028	2,210,313
Property and equipment, net (including property and equipment, net of VIEs of RMB1,421,036 and RMB2,164,121 as of December 31, 2016 and 2017, respectively)	8,165,601	4,322,891
Intangible assets, net (including intangible assets, net of VIEs of RMB54,558 and RMB143,151 as of December 31, 2016 and 2017, respectively)	348,466	92,569
Prepaid land use rights, net	26,245	26,792
Goodwill	1,570,755	1,341,087	¥ 1,294,664
Deferred tax assets (including deferred tax assets of VIEs of RMB8,178 and RMB11,846 as of December 31, 2016 and 2017, respectively)	14,305	12,626
Restricted cash (including restricted cash of VIEs of nil and RMB23,592 as of December 31, 2016 and 2017, respectively)	63,317
VAT recoverable (including VAT recoverable of VIEs of RMB12,094 and RMB26,235 as of December 31, 2016 and 2017, respectively)	290,065	98,863
Other non-current assets (including other non-current assets of VIEs of RMB36,357 and RMB80,763 as of December 31, 2016 and 2017, respectively)	211,785	98,725
Total assets	13,144,567	8,203,866
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 RMB413,600 and RMB232,000 as of December 31, 2016 and 2017, respectively)	790,484	628,478
Accounts payable (including accounts payable of VIEs of RMB152,192 and RMB339,175 as of December 31, 2016 and 2017, respectively)	1,110,411	513,543
Accrued expenses and other payables (including accrued expenses and other payables of VIEs of RMB125,989 and RMB91,542 as of December 31, 2016 and 2017, respectively)	368,624	207,950
Deferred revenue (including deferred revenue of VIEs of RMB30,033 and RMB46,526 as of December 31, 2016 and 2017, respectively)	55,609	40,657
Capital lease and other financing obligations, current (including capital lease and other financing obligations, current of VIEs of RMB55,311 and RMB84,771 as of December 31, 2016 and 2017, respectively)	97,943	88,593
Total current liabilities	2,423,071	1,479,221
Long-term borrowings, excluding current portion (including long-term borrowings, excluding current portion of VIEs of nil and RMB85,250 as of December 31, 2016 and 2017, respectively)	3,459,765	1,509,676
Convertible bonds payable		1,040,550
Capital lease and other financing obligations, non-current (including capital lease and other financing obligations, non-current of VIEs of RMB631,874 and RMB879,685 as of December 31, 2016 and 2017, respectively)	2,303,044	1,022,959
Deferred tax liabilities (including deferred tax liabilities of VIEs of RMB39,426 and RMB70,030 as of December 31, 2016 and 2017, respectively)	124,277	53,280
Other long-term liabilities (including other long-term liabilities of VIEs of RMB8,717 and RMB13,145 as of December 31, 2016 and 2017, respectively)	358,898	111,706
Total liabilities	8,669,055	5,217,392
Shareholders' Equity
Ordinary shares (US$0.00005 par value; 2,002,000,000 shares authorized; 760,009,043 and 941,269,679 shares issued and outstanding as of December 31, 2016 and 2017, respectively)	320	260
Additional paid-in capital	5,861,445	4,036,959
Accumulated other comprehensive loss	(200,688)	(192,080)
Accumulated deficit	(1,185,565)	(858,665)
Total shareholders' equity	4,475,512	2,986,474	¥ (340,505)	¥ (16,565)
Commitments and contingencies
Total liabilities and shareholders' equity	¥ 13,144,567	¥ 8,203,866

CONSOLIDATED BALANCE SHEETS (Parenthetical) ¥ in Thousands	Dec. 31, 2017 CNY (¥) shares	Dec. 31, 2016 CNY (¥) shares
Current assets, VIEs
Cash	¥ 1,873,446	¥ 1,811,319
Restricted cash	10,837	27,673
Accounts receivable, net of allowance for doubtful accounts	364,654	198,851
Value-added-tax ("VAT") recoverable	112,067	72,958
Prepaid expenses	50,373	50,361
Other current assets	42,651	49,151
Property and equipment, net	8,165,601	4,322,891
Intangible assets, net	348,466	92,569
Deferred tax assets	14,305	12,626
Restricted cash, non-current	63,317
VAT recoverable	290,065	98,863
Other non-current assets	211,785	98,725
Current liabilities, VIEs
Short-term borrowings and current portion of long-term borrowings	790,484	628,478
Accounts payable	1,110,411	513,543
Accrued expenses and other payables	368,624	207,950
Deferred revenue	55,609	40,657
Capital lease and other financing obligations, current	97,943	88,593
Long-term borrowings, excluding current portion	3,459,765	1,509,676
Capital lease and other financing obligations, non-current	2,303,044	1,022,959
Deferred tax liabilities	124,277	53,280
Other long-term liabilities	¥ 358,898	¥ 111,706
Ordinary shares, shares authorized \| shares	2,002,000,000	2,002,000,000
Ordinary shares, shares issued \| shares	941,269,679	760,009,043
Ordinary shares, shares outstanding \| shares	941,269,679	760,009,043
VIEs
Current assets, VIEs
Cash	¥ 266,560	¥ 397,948
Restricted cash	10,837	10,091
Accounts receivable, net of allowance for doubtful accounts	348,536	172,538
Value-added-tax ("VAT") recoverable	27,596	13,399
Prepaid expenses	32,919	28,466
Other current assets	7,283	1,201
Property and equipment, net	2,164,121	1,421,036
Intangible assets, net	143,151	54,558
Deferred tax assets	11,846	8,178
Restricted cash, non-current	23,592	0
VAT recoverable	26,235	12,094
Other non-current assets	80,763	36,357
Current liabilities, VIEs
Short-term borrowings and current portion of long-term borrowings	232,000	413,600
Accounts payable	339,175	152,192
Accrued expenses and other payables	91,542	125,989
Deferred revenue	46,526	30,033
Capital lease and other financing obligations, current	84,771	55,311
Long-term borrowings, excluding current portion	85,250	0
Capital lease and other financing obligations, non-current	879,685	631,874
Deferred tax liabilities	70,030	39,426
Other long-term liabilities	¥ 13,145	¥ 8,717

CONSOLIDATED STATEMENTS OF OPERATIONS - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF OPERATIONS
Net revenue	¥ 1,616,166	¥ 1,055,960	¥ 703,636
Cost of revenue	(1,207,694)	(790,286)	(514,997)
Gross profit	408,472	265,674	188,639
Operating expenses
Selling and marketing expenses	(90,118)	(71,578)	(57,588)
General and administrative expenses	(228,864)	(227,370)	(128,714)
Research and development expenses	(7,261)	(9,100)	(3,554)
(Loss) Income from operations	82,229	(42,374)	(1,217)
Other income (expenses):
Interest income	5,600	2,070	1,355
Interest expenses	(412,003)	(265,234)	(126,901)
Foreign currency exchange gain (loss), net	(12,299)	18,310	11,107
Government grants	3,062	2,217	3,915
Others, net	435	284	1,174
Loss before income taxes	(332,976)	(284,727)	(110,567)
Income tax benefits	6,076	8,315	11,983
Net loss	(326,900)	(276,412)	(98,584)
Change in redemption value of redeemable preferred shares		205,670	(110,926)
(Cumulative) Dividend on preferred shares		(332,660)	(7,127)
Net loss attributable to ordinary shareholders	¥ (326,900)	¥ (403,402)	¥ (216,637)
Loss per ordinary share
Basic and diluted (in CNY per share)	¥ (0.42)	¥ (1.35)	¥ (0.99)
Weighted average number of ordinary share outstanding
Basic and diluted (in shares)	784,566,371	299,093,937	217,987,922

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
Net loss	¥ (326,900)	¥ (276,412)	¥ (98,584)
Other comprehensive loss
Foreign currency translation adjustments, net of nil tax	(8,608)	(130,131)	(118,491)
Comprehensive loss	¥ (335,508)	¥ (406,543)	¥ (217,075)

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
Foreign currency translation adjustments, tax	¥ 0	¥ 0	¥ 0

CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY (DEFICIT) - CNY (¥) ¥ in Thousands	Ordinary Shares	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit	Total
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 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
Changes in shareholders deficit
Loss for the year				(276,412)	(276,412)
Other comprehensive loss			(130,131)		(130,131)
Comprehensive loss			(130,131)	(276,412)	(406,543)
Change in redemption value of redeemable preferred shares		205,670			205,670
Share-based compensation		64,165			64,165
Issuance of ordinary shares	¥ 54	1,221,464			1,221,518
Issuance of ordinary shares - (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 convertible securities	¥ 118	2,311,014			2,311,132
Conversion of convertible securities (in shares)	349,087,677
Settlement of liability-classified restricted shares award	¥ 1	7,538			7,539
Settlement of liability-classified restricted shares award (in shares)	877,400
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
Changes in shareholders deficit
Loss for the year				(326,900)	¥ (326,900)
Other comprehensive loss			(8,608)		(8,608)
Comprehensive loss			(8,608)	(326,900)	(335,508)
Share-based compensation		59,843			59,843
Issuance of ordinary shares	¥ 21	649,813			649,834
Issuance of ordinary shares - (in shares)	64,257,028
Conversion of convertible bonds	¥ 32	1,106,195			1,106,227
Conversion of convertible bonds (in shares)	97,870,263
Settlement of liability-classified restricted shares award		4,462			4,462
Settlement of liability-classified restricted shares award (in shares)	502,000
Shares surrendered (in shares)	(866,655)
Shares issued to depository bank	¥ 7	(7)
Shares issued to depository bank (in shares)	20,000,000
Exercise of share options		4,180			¥ 4,180
Exercise of share options (in shares)	816,880				816,880
Vesting of restricted shares (in shares)	1,621,120
Settlement of share options and restricted share awards with shares held by depository bank (in shares)	(2,940,000)
Balance at Dec. 31, 2017	¥ 320	¥ 5,861,445	¥ (200,688)	¥ (1,185,565)	¥ 4,475,512
Balance (in shares) at Dec. 31, 2017	941,269,679				941,269,679

CONSOLIDATED STATEMENTS OF CASH FLOWS ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)
Cash flows from operating activities:
Net loss	¥ (326,900)	¥ (276,412)	¥ (98,584)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of debt issuance cost and debt discount	48,100	5,917
Depreciation and amortization	378,130	227,355	145,406
Net gain on disposal of property and equipment		(62)
Share-based compensation expense	59,843	64,165	4,061
Reversal of allowance for doubtful accounts		(2,156)
Deferred tax benefit	(11,622)	(10,624)	(10,589)
Changes in operating assets and liabilities, net of effect of acquisitions:
Increase of accounts receivable	(134,631)	(79,383)	(37,647)
Increase of VAT recoverable	(194,335)	(94,588)	(41,431)
(Increase) decrease of prepaid expenses	520	1,034	(15,017)
Increase of restricted cash	(9,762)	(21,248)	(6,425)
(Increase) decrease of other current assets	11,500	(20,534)	(12,287)
Increase of other non-current assets	(23,111)	(24,820)	(22,766)
(Decrease) increase of accounts payable	33,903	43,844	(5,150)
Increase (decrease) of due to related parties		(2,668)	2,668
Increase (decrease) of deferred revenue	14,952	(5,851)	3,207
(Decrease) increase of accrued expenses and other payables	(80,294)	22,018	(1,071)
Increase of other long-term liabilities	59,095	23,785	15,327
Net cash used in operating activities	(174,612)	(150,228)	(80,298)
Cash flows from investing activities
Payments for purchase of property and equipment	(1,720,165)	(987,763)	(732,979)
Payments for purchase of intangible assets	(6,000)
Loans advanced to subsidiaries prior to acquisitions	(6,025)	(42,000)
Cash acquired from the acquisition of subsidiaries	21,297	1,237
Cash paid for the acquisition of subsidiaries	(279,885)	(103,600)
Deposit paid for potential acquisitions	(5,000)	(15,000)
Proceeds from sale of property and equipment		62	52
Deposits paid for construction of property and equipment	(40,000)
Release of restricted cash related to purchase of property and equipment			1,022
Net cash used in investing activities	(2,035,778)	(1,147,064)	(731,905)
Cash flows from financing activities:
Proceeds from short-term borrowings	553,490	339,777	333,000
Proceeds from long-term borrowings	3,086,390	1,269,996	584,457
Repayment of short-term borrowings	(381,071)	(433,000)	(289,000)
Repayment of long-term borrowings	(1,401,023)	(373,946)	(137,709)
Payment of issuance cost of borrowings	(62,460)	(57,438)	(24,310)
Proceeds from exercise of stock options	3,377
Proceeds from issuance of convertible bonds		327,580	648,950
Repayment of bonds payable			(14,330)
Proceeds from a related party loan			64,936
Repayment of a related party loan		(65,474)
Net proceeds from issuance of ordinary shares	649,834	1,221,518
Payment of preferred shares dividends		(76,502)
Repurchase of redeemable preferred shares			(23,300)
Payment under capital lease and other financing obligations	(68,670)	(23,897)	(17,934)
Restricted cash deposited related to borrowings	(33,100)
Restricted cash released upon repayment of borrowings			2,925
Net cash provided by financing activities	2,346,767	2,128,614	1,127,685
Effect of exchange rate changes on cash	(74,250)	55,499	2,258
Net increase in cash	62,127	886,821	317,740
Cash at beginning of year	1,811,319	924,498	606,758
Cash at end of year	1,873,446	1,811,319	924,498
Supplemental disclosures of cash flow information
Interest paid	358,748	228,678	81,216
Income tax paid	1,369	5,645	853
Supplemental disclosures of non-cash investing and financing activities
(Settlement of) payables for purchase of property and equipment	(287,327)	128,901	20,402
Purchase of property and equipment through capital leases and other financing arrangement	828,452	568,984	¥ 205,000
Changes in consideration payable for the acquisition of subsidiaries.	254,470	25,900
Issuance of ordinary shares to settle preference dividend		¥ 266,794
Conversion of convertible bonds	¥ 1,106,227

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	12 Months Ended
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	Dec. 31, 2017
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	1DESCRIPTION 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, Sichuan Province and Hebei 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.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

12 Months Ended

Dec. 31, 2017

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 certain data center related 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 GDS (Shanghai) Investment Co., Ltd. (formerly known as 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 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 Accounting Standards Codification (“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, 2015, 2016 and 2017 are as follows:

	Years ended December 31,
	2015		2016		2017

Net revenue	30,598		846,168		1,469,929
Net (loss) income	(5,327	)	22,246		44,541
Net cash provided by operating activities	8,631		239,624		183,180
Net cash used in investing activities	(1,456	)	(158,681	)	(286,476	)
Net cash provided by (used in) financing activities	—		304,973		(28,092	)

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.

Costs recognized by the VIEs for outsourcing and other services provided by other entities within the Company were RMB7,506, RMB343,271 and RMB658,617 for the years ended December 31, 2015, 2016 and 2017, respectively.

(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, the fair value of leased property 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.

(c)Cash and cash equivalents

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, 2016 and 2017.

(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 receivable 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, 2017, 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.

If at any time the lessee and lessor agree to change the provisions of the lease, other than by renewing the lease or extending its term, in a manner that would have resulted in a different classification of the lease under the lease classification criteria had the changed terms been in effect at lease inception, the revised agreement shall be considered as a new agreement over its term, and the lease classification criteria shall be applied for purposes of classifying the new lease.

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, 2016 and 2017, 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, 2015		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
Additions		7,394
Accretion expense		949

Asset retirement obligations as of December 31, 2017		17,648

(k)Intangible assets

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

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

Customer relationships		5-15 years
Favorable leases		20 years
Licenses		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.

Licenses are amortized using a straight-line method over the estimated beneficial period.

(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, 2015, 2016 and 2017.

(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, 2015, 2016 and 2017.

(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, 2017, the Company recorded a VAT recoverable of RMB112,067 (2016: RMB72,958) in current assets and RMB290,065 (2016: RMB98,863) in non-current assets and VAT payables of RMB11,213 (2016: RMB5,954) 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 10 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, including offering direct private connection to major Cloud platforms and providing Cloud infrastructure and solutions to assist customers in managing their hybrid Clouds. 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 RMB3,554, RMB9,100 and RMB7,261 in 2015, 2016 and 2017, 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 RMB4,128, RMB8,942 and RMB10,189 in 2015, 2016 and 2017, 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 RMB25,659, RMB12,976 and RMB7,469 were recorded in general and administrative expenses in 2015, 2016 and 2017, 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. In 2017, the Company received government subsidies that required the Company to pass certain inspection on the related project by March 31, 2019. The Company recorded such subsidies in other long-term liabilities when received and will be recorded as government subsidy income when the conditions are met.

As of December 31, 2016 and 2017, deferred government grants of RMB14,051 and RMB16,789, respectively, 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 2015, 2016 and 2017 is as follows:

	Years ended December 31,
	2015		2016		2017

Total interest costs	138,260		324,085		466,460
Less: interest costs capitalized	(11,359	)	(58,851	)	(54,457	)

Interest expenses	126,901		265,234		412,003

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.

Unamortised debt issuance costs of RMB74,246 and RMB134,395 are presented as a reduction of debt as of December 31, 2016 and 2017, 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.

(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 share-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 gain (loss) 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 RMB501,125 and RMB458,971 as of December 31, 2016 and 2017, respectively.

As of December 31, 2017, the Company’s cash and restricted cash were deposited in major financial institutions located in PRC and Hong Kong financial institutions, and were denominated in the following currencies:

	RMB	USD	HKD	JPY	EUR
In PRC	446,621	34,437	—	—	—
In Hong Kong	12,350	189,632	27,126	10,630	158

Total in original currency	458,971	224,069	27,126	10,630	158

RMB equivalent	458,971	1,464,108	22,675	615	1,231

(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 Issued Accounting Standards

In May 2017, Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2017-09, Compensation—Stock Compensation (Topic 718). This ASU was issued primarily to provide clarity and reduce both diversity in practice and cost and complexity when applying the guidance in Topic 718 to a change to the terms or conditions of a share-based payment award. This ASU affects any entity that changes the terms or conditions of a share-based payment award. This ASU provides guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. This ASU is effective for annual or any interim reporting periods beginning after December 15, 2017 with early adoption permitted. The adoption of this standard is not expected to have a significant impact on the Company’s consolidated financial statements.

In January 2017, FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. This ASU is to simplify the subsequent measurement of goodwill. The ASU eliminates step 2 from the goodwill impairment test and the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails that qualitative test, to perform step 2 of the goodwill impairment test. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. This ASU should be applied on a prospective basis. This ASU is effective for the Company for its annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company is currently evaluating the impact that the adoption of this standard will have on the its consolidated financial statements.

In January 2017, FASB issued ASU No. 2017-03, Accounting Changes and Error Corrections (Topic 250). The ASU adds SEC disclosure requirements for both the quantitative and qualitative impacts that certain recently issued accounting standards will have on the financial statements of a registrant when such standards are adopted in a future period. Specially, these disclosure requirements apply to the adoption of ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606); ASU No. 2016-02, Leases (Topic 842); and ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This ASU is effective immediately.

In January 2017, FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business. The ASU affects all companies and other reporting organizations that must determine whether they have acquired or sold a business. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. The ASU is effective for annual periods beginning after December 15, 2017, including interim periods within those periods with early adoption being permitted. The adoption of this standard is not expected to have a significant impact on the Company’s consolidated financial statements.

In November 2016, FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. This ASU applies to all entities that have restricted cash or restricted cash equivalents and are required to present a statement of cash flows. The ASU requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. This ASU is effective for the Company for its fiscal years beginning after December 15, 2017, and interim periods within those fiscal years with early adoption being permitted. The amendments in this update should be applied using a retrospective transition method to each period presented. The adoption of this ASU will affect the presentation of restricted cash of RMB27,673 and RMB74,154 as of December 31, 2016 and December 31, 2017, respectively.

In October 2016, FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory. This ASU requires the recognition of the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. This ASU is effective for fiscal years and interim period within those fiscal years, beginning after December 15, 2017, with early adoption permitted. The adoption of this standard is not expected to have a significant impact on the Company’s consolidated financial statements.

In August 2016, FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. This ASU provides guidance on the classification of eight cash flow issues to reduce the existing diversification in practice, including (a) debt prepayment or debt extinguishment costs; (b) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; (c) contingent consideration payments made after a business combination; (d) proceeds from settlement of insurance claims; (e) proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies; (f) distributions received from equity method investees; (g) beneficial interests in securitization transactions; and (h) separately identifiable cash flows and application of the predominance principle. The ASU is effective for fiscal years and interim period within those fiscal years, beginning after December 15, 2017, with early adoption permitted. The adoption of this standard is not expected to have a significant impact on the Company’s consolidated financial statements.

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 fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, with early adoption permitted. While the Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements, the Company currently believes the most significant changes relate to the recognition of right-of-use (“ROU”) assets and lease liabilities on its balance sheet for operating leases of the building of certain data centers. As of December 31, 2017, the Company had operating lease commitments expiring within 20 years from the inception of the leases. The total amount of the Company’s future minimum lease payments under operating leases was RMB760,355 as of December 31, 2017.

In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”) Topic 606 and issued subsequent amendments to the initial guidance within ASU 2015-14, ASU 2016-08, ASU 2016-10, ASU 2016-12, ASU 2016-20, ASU 2017-13 and ASU 2017-14 collectively referred as “Topic 606”. Topic 606 will replace most existing revenue recognition guidance in U.S. GAAP. The core principle of Topic 606 is that an entity should recognize revenue for the transfer of goods or services equal to the amount that it expects to be entitled to receive for those goods or services. Topic 606 requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments.

Topic 606 allows entities to adopt with one of these two methods: full retrospective, which applies retrospectively to each prior reporting period presented, or modified retrospective, which recognizes the cumulative effect of initially applying the revenue standard as an adjustment to the opening balance of retained earnings in the period of initial application. The Company currently anticipates adopting the standard using the modified retrospective method.

Topic 606, as amended, is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods therein (i.e., January 1, 2018, for a calendar year entity). Early application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The Company will adopt the standard on January 1, 2018.

Based on the revenue of its customer contracts, the Company expects that revenue on the majority of its customer contracts will continue to be recognized over the contract terms, consistent with its current revenue recognition accounting policy. The adoption of this standard is not expected to have a significant impact on the Company’s consolidated financial statements.

ACCOUNTS RECEIVABLE, NET

12 Months Ended

Dec. 31, 2017

ACCOUNTS RECEIVABLE, NET

ACCOUNTS RECEIVABLE, NET

3ACCOUNTS RECEIVABLE, NET

Accounts receivable, net consisted of the following:

	As of December 31,
	2016	2017

Accounts receivable	198,851	364,654
Less: allowance for doubtful accounts	—	—

Accounts receivable, net	198,851	364,654

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 receivable included an unbilled portion of RMB117,192 and RMB253,724 as of December 31, 2016 and 2017, respectively.

Accounts receivable of RMB87,347 and RMB136,043 was pledged as security for bank loans (note 10) as of December 31, 2016 and 2017, 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:

	Years ended December 31,
	2015	2016		2017

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


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

During the year ended December 31, 2016, the Company reversed allowance for doubtful accounts on a receivable from a customer of RMB2,156 due to the collection of such balance during 2016. Management believes all other accounts receivable as of December 31, 2016 and 2017 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, 2017

OTHER CURRENT ASSETS

OTHER CURRENT ASSETS

4OTHER CURRENT ASSETS

Other current assets consisted of the following:

	As of December 31,
	2016	2017

Rental and other deposits	30,136	23,866
Assets held for sale	18,531	18,531
Others	484	254

	49,151	42,651

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, 2017

PROPERTY AND EQUIPMENT, NET

PROPERTY AND EQUIPMENT, NET

5PROPERTY AND EQUIPMENT, NET

Property and equipment consisted of the following:

	As of December 31, 2016		As of December 31, 2017

At cost:
Buildings	1,652,641		2,693,843
Data center equipment	1,349,069		2,202,247
Leasehold improvement	1,202,979		2,243,691
Furniture and office equipment	31,270		36,762
Vehicles	3,199		2,972

	4,239,158		7,179,515
Less: Accumulated depreciation	(613,658	)	(965,758	)

	3,625,500		6,213,757
Construction in progress	697,391		1,951,844

Property and equipment, net	4,322,891		8,165,601

(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 of December 31, 2016		As of December 31, 2017

At cost (note):
Buildings	1,286,079		2,488,522
Data center equipment	26,375		192,946

	1,312,454		2,681,468
Less: Accumulated depreciation	(64,151	)	(141,948	)

	1,248,303		2,539,520

Note: This item included buildings under construction of RMB313,721 and RMB476,489 and data center equipment under construction of nil and RMB180,228, respectively, as of December 31, 2016 and 2017,

(2)

Depreciation of property and equipment (including assets acquired under capital leases and other financing arrangement) was RMB135,864, RMB212,873 and RMB352,480 for the years ended December 31, 2015, 2016 and 2017, respectively, and included in the following captions:

	Years ended December 31,
	2015	2016	2017

Cost of revenue	131,097	206,724	345,025
General and administrative expenses	4,767	5,425	6,902
Research and development expenses	—	724	553

	135,864	212,873	352,480

(3)

Property and equipment with net a book value of RMB512,566 and RMB698,922 was pledged as security for bank loans (note 10) as of December 31, 2016 and 2017, respectively.

(4)

As of December 31, 2016 and 2017, payables for purchase of property and equipment that are contractually due beyond one year of RMB37,126 and RMB195,749 are recorded in other long-term liabilities in the consolidated balance sheets.

INTANGIBLE ASSETS, NET

12 Months Ended

Dec. 31, 2017

INTANGIBLE ASSETS, NET

INTANGIBLE ASSETS, NET

6INTANGIBLE ASSETS, NET

Intangible assets consisted of the following:

	Note	As of December 31, 2016		As of December 31, 2017

Customer relationships	8	104,322		379,322
Favorable leases	8	15,500		15,500
Licenses		—		6,000

		119,822		400,822
Less: accumulated amortization		(27,253	)	(52,356	)

Intangible assets, net		92,569		348,466

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

Amortization of intangible assets was RMB8,925, RMB13,866 and RMB25,103 for the years ended December 31, 2015, 2016 and 2017, respectively.

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

Fiscal year ending December 31,
2018		37,829
2019		37,829
2020		29,680
2021		29,680
2022		29,680
Thereafter		183,768

Total		348,466

PREPAID LAND USE RIGHTS

12 Months Ended

Dec. 31, 2017

PREPAID LAND USE RIGHTS

PREPAID LAND USE RIGHTS

7PREPAID LAND USE RIGHTS

Prepaid land use rights consisted of the following:

	As of December 31,
	2016		2017

Prepaid land use rights	28,370		28,370
Less: Accumulated amortization	(1,578	)	(2,125	)

Prepaid land use rights, net	26,792		26,245

Amortization of prepaid land use rights was RMB617, RMB616 and RMB547 for the years ended December 31, 2015, 2016 and 2017, respectively.

Prepaid land use rights with a net book value of RMB20,735 and RMB6,091 were pledged as security for bank loans (note 10) as of December 2016 and 2017, respectively.

BUSINESS COMBINATIONS

12 Months Ended

Dec. 31, 2017

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS

8BUSINESS COMBINATIONS

The movement of goodwill is set out as below:

	As of December 31,
	2016	2017

Balance at the beginning of the year	1,294,664	1,341,087
Addition during the year	46,423	229,668

Balance at end of year	1,341,087	1,570,755

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.

Guangzhou 1 Acquisition

On May 19, 2016, the Company acquired all of the equity interests in Guangzhou Weiteng Construction Co., Ltd. (“Weiteng Construction”) 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 were paid in 2017.

Weiteng Construction is a limited liability company organized and existing under the PRC law and owns a data center project (“Guangzhou 1”) in Guangzhou, China. 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, in February and May 2016, the Company lent short-term loans of RMB40,000 and RMB2,000, respectively, to Weiteng Construction. 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 Weiteng Construction. At the acquisition date, the amount due from Weiteng Construction of RMB43,161, 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. 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 Weiteng Construction 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 Weiteng Construction 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.

Shenzhen 5 Acquisition

On June 29, 2017, the Company consummated an acquisition of all equity interests in a target group from a third party for an aggregate contingent purchase price of RMB312,000, of which RMB69,832 was paid up to December 31, 2017. The Company estimated that, pursuant to the share purchase agreement, all specified conditions would be met and the Company would be obligated to settle full amount of the purchase price of RMB312,000.

The target group owns a data center project (“Shenzhen 5”) in Shenzhen, China. At the date of acquisition, the data center had 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	(i)	294,491
Effective settlement of pre-existing relationships upon consolidation	(ii)	6,025
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash		(11,153	)
Property and equipment	(iii)	(821,405	)
Identifiable intangible assets	(iv)	(176,500	)
Other assets		(59,520	)
Accounts payable		219,207
Capital lease and other financing obligations, current		23,156
Capital lease and other financing obligations, non-current		363,380
Long-term borrowings		217,790
Deferred tax liabilities		45,931
Other liabilities		55,299

Total identifiable net assets		(143,815	)

Goodwill	(v)	156,701

Note (i):	The fair value of consideration represents the present value of the purchase price of RMB312,000, of which RMB69,832 was paid up to December 31, 2017. As of December 31, 2017, total consideration payable for the acquisition was RMB230,539. The payment schedule of remaining consideration is based on the milestone related to the achievement of all specified conditions. RMB109,658 and RMB120,881 were recorded in other payables and other long-term liabilities, respectively as of December 31, 2017.

Note (ii):	Prior to the acquisition, the Company had other receivables from the target group of RMB6,025, which was effectively settled with the seller upon completion of the acquisition.

Note (iii):	Property and equipment acquired included properties and equipment acquired under capital lease and other financing arrangement of RMB416,000, data center equipment of RMB174,292, leasehold improvements of RMB118,368 and construction in progress of RMB112,745.

Note (iv):	Identifiable intangible assets acquired consisted of customer relationships of RMB176,500 with an estimated useful life of 14.4 years.

Note (v):	Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in the acquisition. 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 the target group 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 ASC 350, goodwill is not amortized but is tested for impairment.

The amounts of net revenue and net loss of the target group included in the Company’s consolidated statements of operations from the acquisition date to December 31, 2017 amounted to RMB42,072 and RMB23,859, respectively.

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

Guangzhou 2 Acquisition

On October 9, 2017, the Company consummated an acquisition of all equity interests in a target group from a third party for a cash consideration of RMB233,984, of which RMB184,153 was paid up to December 31, 2017 and the remaining consideration payable was recorded in accrued expenses and other payables.

The target group owns a data center project (“Guangzhou 2”) in Guangzhou, China.

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		233,984
Effective settlement of pre-existing relationships upon consolidation	(i)	(1,807	)
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash		(10,144	)
Accounts receivable		(25,177	)
Property and equipment	(ii)	(319,943	)
Identifiable intangible assets	(iii)	(98,500	)
Other assets		(14,135	)
Accounts payable		56,431
Capital lease and other financing obligations, current		5,958
Capital lease and other financing obligations, non-current		101,875
Short-term borrowings		50,750
Long-term borrowings		52,999
Deferred tax liabilities		35,097
Other liabilities		5,579

Total identifiable net assets		(159,210	)

Goodwill	(iv)	72,967

Note (i):	Prior to the acquisition, the Company had payables to the target group of RMB1,807, which was effectively settled with the seller upon completion of the acquisition.

Note (ii):	Property and equipment acquired included properties and equipment acquired under capital lease and other financing arrangement of RMB106,000, data center equipment of RMB57,932, leasehold improvement of RMB155,149 and furniture and office equipment of RMB862.

Note (iii):	Identifiable intangible assets acquired consisted of customer relationships of RMB98,500 with an estimated useful life of 11.8 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. 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 the target group 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 ASC 350, goodwill is not amortized but is tested for impairment.

The amounts of net revenue and net income of the target group included in the Company’s consolidated statements of operations from the acquisition date to December 31, 2017 amounted to RMB26,573 and RMB2,734, respectively.

OTHER NON-CURRENT ASSETS

12 Months Ended

Dec. 31, 2017

OTHER NON-CURRENT ASSETS

OTHER NON-CURRENT ASSETS

9OTHER NON-CURRENT ASSETS

Other non-current assets consisted of the following:

	As of December 31,
	2016	2017

Rental and other deposits	77,985	193,626
Others	20,740	18,159

	98,725	211,785

Rental and other deposits amounted to RMB77,985 and RMB193,626 as of December 31, 2016 and 2017, respectively, which were expected to be refunded after one year of the balance sheet date. Rental and other deposits expected to be refunded within one year of the balance sheet date, are recorded in other current assets.

LOANS AND BORROWINGS

12 Months Ended

Dec. 31, 2017

LOANS AND BORROWINGS

LOANS AND BORROWINGS

10LOANS AND BORROWINGS

The Company’s borrowings consisted of the following:

	As of December 31, 2016	As of December 31, 2017

Short-term borrowings	239,777	462,946
Current portion of long-term borrowings	388,701	327,538

Sub-total	628,478	790,484
Long-term borrowings, excluding current portion	1,509,676	3,459,765

Total loans and borrowings	2,138,154	4,250,249

Short-term borrowings

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

	As of December 31, 2016	As of December 31, 2017

Unsecured short-term loans and borrowings	—	230,000
Secured short-term loans and borrowings	239,777	232,946


	239,777	462,946

Short-term borrowings were secured by the following assets:

	As of December 31, 2016	As of December 31, 2017

Accounts receivable	19,914	11,615

The weighted average interest rates of short-term borrowings outstanding as of December 31, 2016 and 2017 were 5.27% and 7.93% per annum, respectively.

Long-term borrowings

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

	As of December 31, 2016	As of December 31, 2017

Unsecured long-term loans and borrowings	—	167,250
Secured long-term loans and borrowings	1,898,377	3,620,053

	1,898,377	3,787,303

The weighted average interest rates of long-term borrowings as of December 31, 2016 and 2017 were 8.16% and 6.93% per annum, respectively.

Long-term borrowings were secured by the following assets:

	As of December 31, 2016	As of December 31, 2017

Accounts receivable	67,433	124,428
Property and equipment, net	512,566	698,922
Prepaid land use rights, net	20,735	6,091

	600,734	829,441

Long-term loans of RMB9,500 and nil as of December 31, 2016 and 2017 are guaranteed by William Wei Huang.

The aggregate maturities of the above long-term borrowings for each for the five years and thereafter subsequent to December 31, 2017 are as follows:

Twelve-months ending December 31 ,		Long-term borrowings
2018		327,538
2019		571,091
2020		839,502
2021		1,022,698
2022		715,457
Thereafter		311,017

		3,787,303

As of December 31, 2016 and 2017, the particulars of the total secured long-term loans and borrowings of RMB1,898,377 and RMB3,620,053 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 a local government through a third party bank. As of December 31, 2016 and 2017, the outstanding loans under such credit facility were RMB189,179 and RMB161,000, respectively, and the effective interest rate of the loans was 4.9% per annum. The facility was secured by prepaid land use right with a carrying amount of RMB6,091 as of December 31, 2017 (2016: RMB6,235).

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, 2016, the outstanding loan under such credit facility was RMB199,600 with an effective interest rate of 18.00% per annum. The facility was secured by accounts receivable with a carrying amount of RMB13,367 as of December 31, 2016. In 2017, the Company fully repaid the outstanding loan.

iii)	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, 2016, the outstanding loans under such credit facilities were RMB415,048 (net of debt issuance costs), and the effective interest rate of the loans was 7.72%-7.82% per annum as of December 31, 2016. The outstanding loans under such credit facilities were secured by accounts receivable and property and equipment with a carrying amount of RMB13,305 and RMB153,653 as of December 31, 2016. The Company fully repaid the outstanding loans in 2017.

iv)	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 loans under such facility were 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). As of December 31, 2017, the outstanding loans under such facility were RMB1,024,533 (consisting of a short term working capital loan of RMB45,500 with an effective interest rate of 5.66% per annum and long term loans of RMB979,033 (net of debt issuance costs) with effective interest rates of 7.05%-7.11% per annum). The outstanding loans under such facilities were secured by 1) accounts receivable with a carrying amount of RMB35,185 and RMB8,185 as of December 31, 2017 and 2016, respectively and 2) property and equipment with a carrying amount of RMB92,102 and RMB110,831 as of December 31, 2017 and 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 Wei 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 and 2017, the Company was in compliance with these covenants.

v)	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 loans under such facility were 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). As of December 31, 2017, the outstanding loans under such facility were RMB196,708 (consisting of a short term working capital loan of RMB9,190 with an effective interest rate of 5.87% per annum and long term loans of RMB 187,518 (net of debt issuance costs) with an effective interest rate of 7.24% per annum). The outstanding loans under such facilities were secured by 1) accounts receivable with a carrying amount of RMB25,368 and RMB30,110 as of December 31, 2017 and 2016, respectively and 2) property and equipment with a carrying amount of RMB80,124 and RMB85,765 as of December 31, 2017 and 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 and 2017, the Company was in compliance with these covenants.

vi)	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 loans under such facility were 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) which mature in 2021. The outstanding loans under such facilities were secured by accounts receivable, property and equipment and prepaid land use right with a carrying value of RMB2,466, RMB138,941 and RMB14,500, as of December 31, 2016, respectively. In 2017, the Company fully repaid the outstanding loans.

vii)	As of December 31, 2016, secured long-term loans and borrowings amounted to RMB9,500 with effective interest rate of 5.39% per annum were secured by property and equipment with carrying amount of RMB23,376 and guaranteed by William Wei Huang, Director and CEO of the Company. The Company fully repaid the loans in 2017.

viii)	In March 2017, two subsidiaries of the Company entered into a loan facility agreement with third party banks for a total amount of US$45,000. As of December 31, 2017, the outstanding loans under such agreement were RMB288,872 (net of debt issuance costs) with an effective interest rate of 6.48% per annum. The facility, as amended, mature in April 2020. The loans are required to be repaid in full prior to the maturity date in the event of (a) condition (i), (ii), (iii) and (v) of the Early Repayment Events, or (b) the borrowing subsidiaries cease to, directly or indirectly, own or control 100% of the equity interests of two subsidiaries of the Company. The loan facilities contain financial covenants that limit certain financial ratios, such as the debt to equity ratio, during the relevant period, as defined in the facilities. As of December 31, 2017, the Company was in compliance with these covenants.

ix)	In June 2017, a subsidiary of the Company entered into a project loan facility agreement with a third party bank for a total amount of RMB644,000. As of December 31, 2017, the outstanding loans under such facility were RMB456,706 (net of debt issuance costs), consisting of a short-term working capital loan of RMB22,473 with an effective interest rate of 6.30% per annum and long-term loans of RMB434,233 (net of debt issuance costs) with an effective interest rate of 6.82% per annum. The outstanding long-term loans mature in 2022. The loans were secured by accounts receivable and property and equipment with a carrying amount of RMB14,831 and RMB94,390 as of December 31, 2017, respectively. The loans are required to be repaid in full prior to the maturity date in the event (a) condition (i), (iii) and (v) of the Early Repayment Events, (b) STT GDC ceases to own and control, directly or indirectly, at least 25% of the equity interests of the Company or have the power to cast, or control the casting of, at least 25% of the votes that may be cast at a meeting of the Company’s board of directors (or similar governing body), or ceases to be the single largest shareholder of the Company, (c) the Company ceases to, directly or indirectly, own 100% of the equity interests of GDS Management Company and have the power to control GDS Management Company, (d) GDS Management Company ceases to, directly or indirectly, have the power to control GDS Beijing, (e) GDS Beijing ceases to, directly or indirectly, own 100% of the equity interests of and have the power to control a subsidiary of the Company, or (f) GDS Beijing fails to renew its internet data center (“IDC”) license or the authorization by GDS Beijing to a subsidiary of the Company to operate the business in relation to the related data center pursuant to its IDC license on or before the date of its expiry date. The loan facility contains financial covenants that limit certain financial ratios, including debt service coverage ratio, gross leverage ratio, debt to equity ratio and capital expenditure, as defined in the facility agreement. In addition, the loan includes a cross default if the aggregate amount of Financial Indebtedness or commitment for Financial Indebtedness of any Obligor Party or any other member of the Company is more than RMB50,000. As of December 31, 2017, the Company was in compliance with these covenants.

x)	In September 2017, two subsidiaries of the Company entered into a five-year facility agreement with third party banks for a total amount of RMB570,000 for repayment of borrower’s outstanding loans and financing borrower’s data center located in Beijing. As of December 31, 2017, the outstanding loans under such facility were RMB511,017 (net of debt issuance costs), consisting of a short-term working capital loan of RMB20,000 with an effective interest rate of 5.66%-6.30% per annum and long-term loans of RMB491,017 (net of debt issuance costs) with an effective interest rate of 6.26%-7.13% per annum. The outstanding long-term loans mature in 2022. The loans were secured by accounts receivable and property and equipment with a carrying amount of RMB17,649 and RMB248,377 as of December 31, 2017, respectively. The loans are required to be repaid in full prior to the maturity date in the event (a) condition (i), (iii) and (v) of the Early Repayment Events, (b) STT GDC ceases to own and control, directly or indirectly, at least 25% of the equity interests of the Company or have the power to cast, or control the casting of, at least 25% of the votes that may be cast at a meeting of the Company’s board of directors (or similar governing body), or ceases to be the single largest shareholder of the Company, (c) the Company ceases to, directly or indirectly, own 100% of the equity interests of GDS Management Company and have the power to control GDS Management Company, (d) GDS Management Company ceases to, directly or indirectly, be the beneficial owner of 100% of equity interests of GDS Beijing and GDS Suzhou and have the power to control GDS Beijing and GDS Suzhou, (e) GDS Beijing ceases to, directly or indirectly, be the legal and beneficial owner of 100% of equity interests of GDS Suzhou and have the power to control GDS Suzhou, (f) Beijing Hengpu’an Data Technology Development Co., Ltd. (“BJ Hengpu’an”) ceases to, directly or indirectly, be the legal and beneficial owner of 100% of equity interests of BJ Hengchang and have the power to control Beijing Hengchang Data Science & Technology Development Co., Ltd., or (g) GDS Beijing fails to renew its IDC license or the authorization by GDS Beijing to GDS Suzhou to operate the business in relation to the related data centers pursuant to its IDC license on or before the date of its expiry date. The loan facility contains financial covenants that limit certain financial ratios, including debt service coverage ratio, gross leverage ratio, debt to equity ratio and capital expenditure, as defined in the facility agreement. 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. As of December 31, 2017, the Company was in compliance with these covenants.

xi)	In October 2017, a subsidiary of the Company entered into a 42-month facility agreement with a third-party bank for a total amount of US$25,000. As of December 31, 2017, the outstanding loan under such facility was RMB159,941 (net of debt issuance costs), which was a long-term loan with an effective interest rate of 6.87% per annum. The outstanding long-term loan matures in 2021. The loan was secured by accounts receivable with a carrying amount of RMB3,015 as of December 31, 2017. The loan is 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 25% of the Company’s equity interests or have the power to cast, or control the casting of, at least 25% of the votes that may be cast at a meeting of the Company’s board of directors (or similar governing body), or ceases to be the Company’s single largest shareholder, (iii) the Company cease to, directly or indirectly, own 100% of the equity interests of and have the power to control the target group in Guangzhou 2 Acquisition, (iv) William Wei Huang ceases to, directly or indirectly, own at least 99.9% of the equity interests of GDS Beijing or GDS Suzhou and have the power to control GDS Beijing or GDS Suzhou, (v) the Guangzhou 2 Acquisition does not occur by the long-stop date or the relevant transaction documents are terminated or rescinded or purported to be rescinded or repudiated or purported to be repudiated in whole or in part by any party thereof, or (vi) the IDC license of GDS Beijing or the borrowing subsidiary is cancelled prior to its expiry date. The loan facilities contain financial covenants that limit the debt service cover ratio during the relevant period, as defined in the facilities. In addition, the facility agreement includes a cross default provision which would be triggered if the Company fails to repay any financial indebtedness in an aggregate amount of US$4,500 or more when due or within any originally applicable grace period. As of December 31, 2017, the Company was in compliance with these covenants.

xii)	In November 2017, a subsidiary of the Company entered into a 5-year facility agreement with a third-party bank for a total amount of RMB180,000. As of December 31, 2017, the outstanding loans under such facility were RMB169,984 (net of debt issuance costs), consisting of a short-term working capital loan of RMB15,782 with an effective interest rate of 5.66% per annum and a long-term loan of RMB154,202 (net of debt issuance costs) with an effective interest rate of 6.92% per annum. The outstanding long-term loans mature in 2022. The loans were secured by accounts receivable and property and equipment with a carrying amount of RMB27,003 and RMB183,929 as of December 31, 2017, respectively. The loan is required to be repaid in full prior to the maturity date in the event (a) condition (i), (iii) and (v) of the Early Repayment Events, (b) STT GDC ceases to own and control, directly or indirectly, at least 25% of the Company’s equity interests or have the power to cast, or control the casting of, at least 25% of the votes that may be cast at a meeting of the Company’s board of directors (or similar governing body), or ceases to be the Company’s single largest shareholder, (c) the Company ceases to, directly or indirectly, own 100% of the equity interests of and have the power to control GDS Management Company, GDS Suzhou or GDS Beijing, or (d) GDS Beijing or the borrowing subsidiary fails to renew its IDC License on or before the date of its expiry date. The loan facilities contain financial covenants that limit certain financial ratios, such as the debt service coverage ratio and gross leverage ratio, during the relevant period, as defined in the facilities. In addition, the facility agreement 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. As of December 31, 2017, the Company was in compliance with these covenants.

xiii)	In November 2017, a subsidiary of the Company entered into a 6-year facility agreement with a third-party bank for a total amount of RMB428,000 for replacement of existing loans. As of December 31, 2017, the outstanding loans under such facility were RMB402,057 (net of debt issuance costs), which were long-term loans with an effective interest rate of 6.38% per annum. The outstanding long-term loans mature in 2023.

xiv)	In November 2017, a subsidiary of the Company entered into a financing arrangement with a third-party financer, which was amended in December 2017. Under such arrangement, the subsidiary assigned certain existing and future receivables as security in exchange for a cash payment of RMB200,000, which had not been received as of December 31, 2017. The subsidiary is obligated to repay RMB 200,000 together with an effective interest rate of 9.70% per annum within 5 years.

xv)	In December 2017, a subsidiary of the Company entered into a 7-year facility agreement with a third-party bank for a total amount of RMB1,010,000 for the purpose of (i) replacing an existing term loan facility agreement entered into in December 2016 and (ii) financing the subsidiaries’ data center projects and working capital requirements. As of December 31, 2017, the outstanding loan under such facility was RMB309,708 (net of debt issuance costs), which was a long-term loan mature in 2024. As of December 31, 2017, the effective interest rate of the outstanding loan was 7.35% per annum. The Company is required to pay issuance cost of RMB35,540. The loans are secured by accounts receivable with a carrying amount of RMB1,377 as of December 31, 2017.

xvi)	In December 2017, a subsidiary of the Company entered into a 10-year facility agreement with a third-party bank for a total amount of RMB100,000. As of December 31, 2017, the outstanding loan under such facility was RMB52,472 (net of debt issuance costs), which was a long-term loan with an effective interest rate of 6.69% per annum. The outstanding long-term loan matures in 2027.

As of December 31, 2017, the particulars of unsecured long-term loans and borrowings are as follows:

i)	In March 2017, a subsidiary of the Company entered into an agreement with a third party bank for a total amount of RMB9,000. As of December 31, 2017, the outstanding loan was RMB7,250, which is a long-term working capital loan with an effective interest rate of 5.70% per annum and matures in 2019.

ii)	In October 2017, a subsidiary of the Company entered into two facility agreements with third-party banks for a total amount of RMB100,000 and RMB10,000, respectively. As of December 31, 2017, the outstanding loans under such facilities were RMB100,000 and RMB10,000 with an effective interest rate of 5.23% and 7.00%, respectively. The loans mature in October 2019.

iii)	In December 2017, a subsidiary of the Company entered into a facility agreement with a third-party bank for a total amount of RMB50,000. As of December 31, 2017, the outstanding loan under such facility was RMB50,000. The loan bears an effective interest rate of 5.87% and matures in June 2019.

As of December 31, 2017, the Company had total working capital and project financing credit facilities of RMB5,371,555 from various banks, of which the unused amount was RMB986,911. As of December 31, 2017, the Company had drawn down RMB4,384,644, of which RMB462,946 was recorded in short-term loans and borrowings and RMB3,787,303 (net of debt issuance costs of RMB134,395) was recorded in long-term loans and borrowings, respectively. Drawdowns from the credit facility are subject to the approval of the banks and are subject to the terms and conditions of each agreement.

CONVERTIBLE BONDS PAYABLE

12 Months Ended

Dec. 31, 2017

CONVERTIBLE BONDS PAYABLE

CONVERTIBLE BONDS PAYABLE

11CONVERTIBLE BONDS PAYABLE

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. 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:

Maturity Date

December 30, 2019

Interest

A simple rate of 5% per annum on the outstanding principal amount, payable by the Company semi-annually (the “Cash Interest”).

In the event that the bond holder has redeemed or converted part or whole of the principal amount, the bond holder shall be entitled to additional interest with a simple rate of 5% per annum (the “Accrued Interest”), payable in cash on the Maturity Date in the case of redemption or by issuance of ordinary shares of the Company at the Conversion Price on the Conversion Date in the case of conversion.

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.

In November 2017, the bond holders of the Convertible Bonds due 2019, exercised the right to convert 100% of the principal amount of the bonds, together with the Accrued Interest thereon into 97,870,263 newly issued Class A ordinary shares at the conversion price of $1.675262 pursuant to the terms of the bonds. Concurrent with the conversion, the accrued but unpaid Cash Interest was relinquished. The difference between par value of the shares issued of RMB32 and the carrying value of the convertible bonds, Accrued Interest and unpaid Cash Interest of RMB1,106,195 were recorded as additional paid-in capital upon conversion.

ACCRUED EXPENSES AND OTHER PAYABLES

12 Months Ended

Dec. 31, 2017

ACCRUED EXPENSES AND OTHER PAYABLES

ACCRUED EXPENSES AND OTHER PAYABLES

12ACCRUED EXPENSES AND OTHER PAYABLES

Accrued expenses and other payables consisted of the following:

	As of December 31,
	2016	2017

Accrued interest expenses	67,324	21,114
Accrued debt issuance costs	—	34,194
Income tax payable (note 20)	15,265	20,122
Consideration payables for acquisitions (note 8)	25,900	159,489
Other accrued expenses	71,924	101,275
Other payables	27,537	32,430

	207,950	368,624

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

LEASE

12 Months Ended

Dec. 31, 2017

LEASE

LEASE

13LEASE

Capital lease and other financing obligations

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

	December 31, 2016						December 31, 2017
	Capital lease obligations		Other financing obligations		Total		Capital lease obligations		Other financing obligations		Total
Within 1 year	71,300		22,044		93,344		212,780		45,007		257,787
After 1 year but within 2 years	85,783		38,443		124,226		220,293		63,151		283,444
After 2 years but within 3 years	92,677		39,548		132,225		316,475		75,685		392,160
After 3 years but within 4 years	193,202		41,586		234,788		144,052		76,678		220,730
After 4 years but within 5 years	71,501		42,287		113,788		141,910		80,832		222,742
After 5 years	716,089		725,178		1,441,267		1,900,744		1,469,318		3,370,062

Total	1,230,552		909,086		2,139,638		2,936,254		1,810,671		4,746,925

Less total future interest	(552,060	)	(450,670	)	(1,002,730	)	(1,209,120	)	(905,590	)	(2,114,710	)
Less: estimated building costs	—		(25,356	)	(25,356	)	—		(231,228	)	(231,228	)

Present value of lease and other financing obligations	678,492		433,060		1,111,552		1,727,134		673,853		2,400,987

Including:
Current portion					88,593						97,943

Non-current portion					1,022,959						2,303,044

The Company’s capital and build-to-suit leases expire at various dates ranging from 2020 to 2037. The weighted average effective interest rate of the Company’s capital and build-to-suit leases was 8.04% and 7.28% as of December 31, 2016 and 2017, respectively.

The Company recognized the capital lease and other financing obligations assumed in the business combination at the acquisition-date fair value. In addition, the Company entered into the following capital lease arrangements during the year ended December 31, 2017:

Beijing 2 Lease

In August 2017, the Company entered into an amendment agreement in respect of an existing lease of a building in Beijing, China, from a third-party lessor (the “Beijing 2 Lease”). Beijing 2 Lease was originally classified as an operating lease. As a result of the lease modification, the revised agreement was considered as a new lease pursuant to ASC 840-10-25 and was classified as a capital lease as the present value of minimum lease payments excessed 90% of the fair value of the leased assets. Accordingly, the Company recorded capital lease assets and capital lease obligations at an amount equal to the present value of the remaining minimum lease payments of RMB157,000.

Shanghai 5 Lease

In April 2017, the Company entered into a lease agreement for an existing building in Shanghai, China from a third party lessor (the “Shanghai 5 Lease”). Shanghai 5 Lease has a lease term of 20 years and 3 months from July 2017 to September 2037. The Company determined that the lease is a capital lease as the present value of the minimum lease payments exceeded 90% of the fair value of the leased property at the inception of the lease.

Shanghai 8 Lease

In November 2017, the Company entered into a lease agreement for an existing building in Shanghai, China from a third party lessor (the “Shanghai 8 Lease”). Shanghai 8 Lease has a lease term of 20 years from November 2017 to November 2037. The Company determined that the lease is a capital lease as the present value of the minimum lease payments exceeded 90% of the fair value of the leased property at the inception of the lease.

Accordingly, on the 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 RMB262,206 for Shanghai 5 Lease and Shanghai 8 Lease.

Hebei Equipment Lease

In November 2017, the Company entered into a lease agreement with a third party lessor in respect of certain data center equipment (the “Hebei Equipment Lease”). Hebei Equipment Lease has a lease term of 3 years from November 2017 to November 2020. The Company determined that the lease is a capital lease as the present value of the minimum lease payments exceeded 90% of the fair value of the leased equipment at the inception of the lease. Accordingly, on the 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 of RMB177,922.

Build-to-suit leases

Shanghai 6 Lease and Shanghai 7 Lease

In October 2017, the Company entered into a lease agreement with a third party developer-lessor for the development, construction and the lease (build-to-suit lease) of two brand new buildings (the “Shanghai 6 Lease” and “Shanghai 7 Lease”) in Shanghai, China. The Company paid a deposit for the two leases to the developer-lessor. Both the Shanghai 6 Lease and Shanghai 7 Lease have a lease term of 20 years commencing upon the delivery of the respective 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 50% of the remaining 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 levelling 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 2037.

Future minimum operating lease payments as of December 31, 2017 are summarized as follow:

Twelve-months ending December 31,
2018		135,599
2019		101,152
2020		88,587
2021		48,939
2022		48,723
Thereafter		337,355

Total		760,355

Rental expenses were approximately RMB131,875, RMB124,712 and RMB155,148 for the years ended December 31, 2015, 2016 and 2017, respectively. The Company did not sublease any of its operating leases for the periods presented.

OTHER LONG-TERM LIABILITIES

12 Months Ended

Dec. 31, 2017

OTHER LONG-TERM LIABILITIES

OTHER LONG-TERM LIABILITIES

14OTHER LONG-TERM LIABILITIES

Other long-term liabilities consisted of the following:

	As of December 31, 2016	As of December 31, 2017

Consideration payable for an acquisition (Note 8)	—	120,881
Payables for purchase of property and equipment	37,126	195,749
Accrued interests	51,112	—
Deferred government grants	14,051	16,789
Others	9,417	25,479

Total	111,706	358,898

REDEEMABLE PREFERRED SHARES

12 Months Ended

Dec. 31, 2017

REDEEMABLE PREFERRED SHARES

REDEEMABLE PREFERRED SHARES

15REDEEMABLE PREFERRED SHARES

	Series A				Series A*				Series B				Series B1				Series B2				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
Balance at 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 Limited (“EDC Holding”). 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, 2017

FAIR VALUE MEASUREMENT

FAIR VALUE MEASUREMENT

16FAIR VALUE MEASUREMENT

As of December 31, 2016 and 2017, 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, 2017
ORDINARY SHARES
ORDINARY SHARES	17ORDINARY 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. 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. 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). In October 2017, the Company issued 64,257,028 Class A ordinary shares to CyrusOne Inc., a third party investor, at the price of $1.55625 per share. In November 2017, the bond holders of the Convertible Bonds due 2019, exercised the right to convert 100% of the principal amount of the bonds, together with the Accrued Interest thereon into 97,870,263 newly issued Class A ordinary shares at the conversion price of $1.675262 pursuant to the terms of the bonds (note 11). As of December 31, 2017, the Company’s outstanding share capital consisted of 873,679,343 Class A ordinary shares and 67,590,336 Class B ordinary shares.

SHARE-BASED COMPENSATION

12 Months Ended

Dec. 31, 2017

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION

18SHARE-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

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 had an exercise price of US$0.7792 (RMB5.0328) per option. The options have a contractual term of five years.

Options to non-employee consultants

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, 2016 and 2017, 333,334 and nil forfeitable and unvested non-employee options remained unvested, respectively.

A summary of the option activity is as follows:

				Weighted
				average
			Weighted	grant-date
	Number		average	fair value
	of options		exercise price	per option
			(RMB)	(RMB)
Options outstanding at January 1, 2015	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

Granted	333,334		5.2	10.6
Exercised	(816,880	)	5.3	1.9
Forfeited	(19,000	)	5.3	1.9

Options outstanding at December 31, 2017	28,087,236		5.1	3.2


Options vested and expect to vest at December 31, 2017	28,087,236		5.1	3.2

The following table summarizes information with respect to stock options outstanding and stock options exercisable as of December 31, 2017:

		Weighted
		average	Weighted
	Number	remaining	average
	of shares	contractual life	exercise price
		(years)	(RMB)
Options outstanding and exercisable	28,087,236	2.2	5.1

As of December 31, 2016 and 2017, 600,000 and 266,666 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 and 2017, 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:	January 2015	May 2016
Risk-free rate of return	2.27%	1.98%
Volatility	29.80%	28.50%
Expected dividend yield	—	—
Exercise multiple	2.20	2.20
Fair value of underlying ordinary share	US$0.90	US$1.51
	(RMB 5.5)	(RMB 9.8)
Expected term	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.

In May, August and November 2017, the Company issued a total of 502,000 fully vested restricted shares to its directors to settle a portion of their remuneration for services provided by the directors, which had been recorded in general and administrative expenses. The number of restricted shares 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 RMB4,462. 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 and July 2017, the Company granted non-vested restricted shares of 12,910,080 and 13,475,060, respectively, 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
Granted	13,977,060		5.2
Vested	(2,123,120	)	8.5
Forfeited	(238,400	)	6.8

Unvested at December 31, 2017	24,525,620		5.3

The Company recognized share-based compensation expenses of RMB4,697 and RMB56,237 for the years ended December 31, 2016 and 2017, respectively, for the restricted share awards. As of December 31, 2017, total unrecognized compensation expense relating to the unvested shares was RMB81,306. The expense is expected to be recognized over a weighted average period of 1.88 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 years ended December 31, 2016 and 2017.

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	July 2017
Risk-free rate of return	0.68 - 1.65%	1.29 - 1.63%
Volatility	22.35 - 24.80%	20.43 - 21.48%
Expected dividend yield	—	—
Share price at grant date	US$1.24	US$1.191
	(RMB8.6)	(RMB8.0)
Expected term	1 - 5 years	2 - 4 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, 2015, 2016 and 2017 is as follows:

	Years ended December 31,
	2015	2016	2017

Costs of revenue	484	2,114	9,941
Selling and marketing expenses	325	6,590	18,390
General and administrative expenses	3,252	55,409	30,866
Research and development expenses	—	52	646

Total share-based compensation expenses	4,061	64,165	59,843

REVENUE

12 Months Ended

Dec. 31, 2017

REVENUE

REVENUE

19REVENUE

Net revenue consisted of the following:

	Years ended December 31,
	2015	2016	2017

Service revenue	653,591	1,003,015	1,591,860
Equipment sales	50,045	52,945	24,306

	703,636	1,055,960	1,616,166

INCOME TAX

12 Months Ended

Dec. 31, 2017

INCOME TAX

INCOME TAX

20INCOME 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, 2015, 2016 and 2017 are as follows:

	Years ended December 31,
	2015		2016		2017
Loss before income taxes:
PRC	94,190		144,158		130,961
Other jurisdictions	16,377		140,569		202,015
Total loss before income taxes	110,567		284,727		332,976


Current tax expenses:
PRC	(1,650	)	311		5,546
Other jurisdictions	256		1,998		—

Total current tax (benefits) expenses	(1,394	)	2,309		5,546


Deferred tax benefits:
PRC	(10,589	)	(10,935	)	(11,683	)
Other jurisdictions	—		311		61


Total deferred tax benefits	(10,589	)	(10,624	)	(11,622	)



Total income taxes benefits	(11,983	)	(8,315	)	(6,076	)

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,
	2015		2016		2017

PRC enterprise income tax rate	25.0	%	25.0	%	25.0	%
Non-PRC entities not subject to income tax	(3.8	)%	(13.7	)%	(14.8	)%
Tax differential for entities in non-PRC jurisdiction	0.0	%	0.5	%	(0.8	)%
Tax effect of permanent differences	(0.6	)%	(0.3	)%	0.0	%
Change in valuation allowance	(9.4	)%	(8.4	)%	(7.8	)%
Return to provision adjustment	(0.4	)%	(0.2	)%	0.2	%


	10.8	%	2.9	%	1.8	%

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

	As of December 31,
	2016		2017
Deferred tax assets:
Government subsidy	3,763		4,197
Accrued expenses	23,324		14,024
Asset retirement obligation	2,377		4,412
Net operating loss carry forwards	141,749		170,267
Total gross deferred tax assets	171,213		192,900
Valuation allowance on deferred tax assets	(134,935	)	(152,241	)

Deferred tax assets, net of valuation allowance	36,278		40,659


Deferred tax liabilities:
Property and equipment	(36,644	)	(52,417	)
Intangible assets	(22,914	)	(82,305	)
Prepaid land use rights	(1,733	)	(1,693	)
Obligation under capital lease and other financing obligations	(15,641	)	(14,216	)

Total deferred tax liabilities	(76,932	)	(150,631	)


Net deferred tax liabilities	(40,654	)	(109,972	)


Analysis as:
Deferred tax assets	12,626		14,305
Deferred tax liabilities	(53,280	)	(124,277	)

Net deferred tax liabilities	(40,654	)	(109,972	)

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

	Years ended December 31,
	2015	2016	2017

Balance at the beginning of the year	116,403	118,952	134,935
Increase during the year	2,549	15,983	17,306

Balance at the end of the year	118,952	134,935	152,241

Management believes it is more likely than not that the deferred tax asset, net of the valuation allowance as of December 31, 2017, 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, 2017, the valuation allowance of RMB152,241 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.

The net operating losses carry forwards of the Company’s PRC subsidiaries amounted to RMB652,043 as of December 31, 2017, of which RMB193,880, RMB60,137, RMB113,187, RMB76,752 and RMB208,087 will expire if unused by December 31, 2018, 2019, 2020, 2021 and 2022, 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, 2016 and 2017, 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, 2017
DISTRIBUTION OF PROFIT
DISTRIBUTION OF PROFIT	21DISTRIBUTION 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 RMB1,975,175 and RMB2,495,075 as of December 31, 2016 and 2017, respectively, including non-distributable general reserve fund of nil and RMB214 as of December 31, 2016 and 2017, respectively. The parent company financial information of GDS Holdings is disclosed in note 27.

LOSS PER ORDINARY SHARE

12 Months Ended

Dec. 31, 2017

LOSS PER ORDINARY SHARE

LOSS PER ORDINARY SHARE

22LOSS PER ORDINARY SHARE

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

	Years ended December 31,
	2015		2016		2017

Net loss	98,584		276,412		326,900

Change in redemption value of redeemable preferred shares (i)	110,926		(205,670	)	—
(Cumulative) Dividend on preferred shares (ii)	7,127		332,660		—

Net loss attributable to ordinary shareholders	216,637		403,402		326,900


Weighted average number of ordinary shares outstanding-basic and diluted (iii)	217,987,922		299,093,937		784,566,371

Loss per ordinary share - basic and diluted	(0.99	)	(1.35	)	(0.42	)

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 (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 year ended December 31, 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 (note 15) upon the IPO less the cumulative dividend on preferred shares amounting to RMB7,127 for the year ended December 31, 2015.

Note (iii):	During the year ended December 31, 2017, the Company issued 20,000,000 ordinary shares to its share depository bank which have been and will continue to be used to settle stock option and restricted share awards upon their exercise. No consideration was received by the Company for this issuance of ordinary shares. These ordinary shares are legally issued and outstanding but are treated as escrowed shares for accounting purposes and, therefore, have been excluded from the computation of loss per ordinary share. Any ordinary shares not used in the settlement of stock option and restricted share awards will be returned to the Company.

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

	Years ended December 31,
	2015	2016	2017

Share options/restricted shares	17,193,534	41,499,862	52,612,856
Convertible bonds payable	59,692,156	93,977,837	—
Redeemable preferred shares	349,087,677	—	—

Total	425,973,367	135,477,699	52,612,856

SEGMENT INFORMATION	12 Months Ended
SEGMENT INFORMATION	Dec. 31, 2017
SEGMENT INFORMATION
SEGMENT INFORMATION	23SEGMENT 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.

MAJOR CUSTOMERS	12 Months Ended
MAJOR CUSTOMERS	Dec. 31, 2017
MAJOR CUSTOMERS
MAJOR CUSTOMERS	24MAJOR CUSTOMERS During the year ended December 31, 2015, the Company had one customer, which generated over 10% of the Company’s total revenues or RMB141,711. 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. During the year ended December 31, 2017, the Company had three customers, which generated over 10% of the Company’s total revenues or RMB318,359, RMB166,384 and RMB163,719, respectively.

COMMITMENTS

12 Months Ended

Dec. 31, 2017

COMMITMENTS

COMMITMENTS

25COMMITMENTS

(a)Capital commitments

Capital commitments outstanding at December 31, 2016 and 2017 not provided for in the financial statements were as follows:

	As of December 31, 2016	As of December 31, 2017

Contracted for	510,999	1,065,551

(b)Lease commitments

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

RELATED PARTY TRANSACTIONS

12 Months Ended

Dec. 31, 2017

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS

26RELATED 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 2015, 2016 and 2017, the related parties of the Company are as follows:

Name of party		Relationship

William Wei Huang (Mr. Huang)		Director and CEO of the Company
STT GDC		Principal ordinary shareholder of the Company
Global Data Solutions Ltd.		Principal ordinary shareholder of the Company
SBCVC Holdings Limited (“SBCVC”)		Principal ordinary shareholder of the Company

(a)Major transactions with related parties

		Years ended December 31,
		2015	2016	2017

Preference dividends
STT GDC	(i)	—	223,225	—
SBCVC		—	109,665	—
Other non-principal preferred shareholders		—	10,406	—

		—	343,296	—


Loan from a related party	(ii)	64,936	—	—


Repayment of a related party loan	(ii)	—	65,474	—


Convertible bonds from a related party	(ii)	—	327,580	—


Conversion of convertible bonds from a related party	(ii)	—	—	366,958


Interest expenses
STT GDC	(ii)	2,579	32,245	30,078

(b)Balances with related parties

As of December 31, 2016 and 2017, the Company did not have any significant balances with related parties.

Note (i):	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.

Note (ii):	During the year ended December 31, 2015, the Company borrowed a loan of US$10,000 (RMB64,936) from STT GDC. The interest expenses on the loan amounted to US$397(RMB2,579).

	On January 29, 2016, the Company received the second tranche of US$50,000 (RMB327,580) from STT GDC 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 years ended December 31, 2016 and 2017, the related interest expense arising from the Convertible Bonds due 2019 subscribed by STT GDC amounted to RMB32,245 and RMB30,078, respectively.

	In November 2017, the Convertible Bonds due 2019 and the Accrued Interest thereon due to STT GDC were fully converted into 32,540,515 newly issued Class A ordinary shares at the conversion price of $1.675262. In addition, upon conversion, the accrued but unpaid Cash Interest due to STT GDC of RMB4,991 was relinquished.

PARENT ONLY FINANCIAL INFORMATION

12 Months Ended

Dec. 31, 2017

PARENT ONLY FINANCIAL INFORMATION

PARENT ONLY FINANCIAL INFORMATION

27PARENT 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, 2017, 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 of December 31,
	2016		2017
Assets

Current assets
Cash	1,030,627		999,194
Prepaid expenses	1,011		6,295
Total current assets	1,031,638		1,005,489
Investment and loans to subsidiaries	3,054,835		3,477,331
Other non-current assets	15,856		14,936
Total assets	4,102,329		4,497,756

Liabilities and Shareholders’ Equity

Current liabilities
Accounts payable	—		3,597
Accrued expenses and other payables	23,266		9,973
Due to subsidiaries	927		843
Total current liabilities	24,193		14,413

Convertible bonds payable	1,040,550		—
Other long-term liabilities	51,112		7,831
Total liabilities	1,115,855		22,244

Shareholders’ equity
Ordinary shares (US$0.00005 par value; 2,002,000,000 shares authorized; 760,009,043 and 941,269,679 shares issued and outstanding as of December 31, 2016 and 2017, respectively)	260		320
Additional paid-in capital	4,036,959		5,861,445
Accumulated other comprehensive loss	(192,080	)	(200,688	)
Accumulated deficit	(858,665	)	(1,185,565	)

Total shareholders’ equity	2,986,474		4,475,512

Commitments and contingencies

Total liabilities and shareholders’ equity	4,102,329		4,497,756

Condensed Statements of Operations

	Years ended December 31,
	2015		2016		2017

Net revenue	—		—		—
Cost of revenue	—		(2,381	)	(10,392	)

Gross loss	—		(2,381	)	(10,392	)

Operating expenses
Selling and marketing expenses	(1,566	)	(8,914	)	(22,528	)
General and administrative expenses	(14,665	)	(82,794	)	(59,500	)
Research and development expenses	—		(52	)	(646	)

Loss from operations	(16,231	)	(94,141	)	(93,066	)

Other income (expenses):
Interest income	—		16		3,901
Interest expenses	(3,297	)	(97,603	)	(90,408	)
Equity in loss of subsidiaries	(79,056	)	(84,952	)	(147,340	)
Others, net	—		268		13

Loss before income taxes	(98,584	)	(276,412	)	(326,900	)

Income tax expenses	—		—		—

Net loss	(98,584	)	(276,412	)	(326,900	)

Condensed Statements of Comprehensive Loss

	Years ended December 31,
	2015		2016		2017

Net loss	(98,584	)	(276,412	)	(326,900	)
Other comprehensive loss:
Foreign currency translation adjustments, net of nil tax	(118,491	)	(130,131	)	(8,608	)

Comprehensive loss	(217,075	)	(406,543	)	(335,508	)

Condensed Statements of Cash Flows

	Years ended December 31,
	2015		2016		2017

Operating activities:
Net cash used in operating activities	(4,895	)	(62,591	)	(58,068	)

Investing activities
Deposit paid for a potential acquisition	—		(15,000	)	—
Increase of due from subsidiaries	(93,101	)	(990,617	)	(588,768	)

Net cash used in investing activities	(93,101	)	(1,005,617	)	(588,768	)


Financing activities:
Proceeds from exercise of stock options	—		—		3,377
Proceeds from issuance of convertible bonds	648,950		327,580		—
Repayment of bonds payable	(14,330	)	—		—
Proceeds from a related party loan	64,936		—		—
Repayment of a related party loan	—		(65,474	)	—
Net proceeds from issuance of ordinary shares	—		1,221,518		649,834
Payment of preferred shares dividends	—		(76,502	)	—
Repurchase of redeemable preferred shares	(23,300	)	—		—

Net cash provided by financing activities	676,256		1,407,122		653,211
Effect of exchange rate changes on cash	57,565		47,787		(37,808	)


Net increase (decrease) in cash	635,825		386,701		(31,433	)
Cash at beginning of year	8,101		643,926		1,030,627

Cash at end of year	643,926		1,030,627		999,194


Supplemental disclosures of cash flow information
Interest paid	3,463		45,495		33,920

Supplemental disclosures of non-cash investing and financing activities
Issuance of ordinary shares to settle preference dividend	—		266,794		—
Conversion of convertible bonds	—		—		1,106,227

- 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, 2017
SUBSEQUENT EVENTS
SUBSEQUENT EVENTS	28SUBSEQUENT EVENTS Issuance of ordinary shares On January 26, 2018, the Company completed a public offering in which the Company offered and sold 8,000,000 ADSs (or 64,000,000 Class A ordinary shares), and SBCVC, one of the Company’s principal shareholders, sold 3,000,000 ADSs (or 24,000,000 Class A ordinary shares), at a price of US$26.00 per ADS. On January 29, 2018, the underwriters exercised their option to purchase from the Company and SBCVC additional 225,000 ADSs (or 1,800,000 Class A ordinary shares) and 1,425,000 ADSs (or 11,400,000 Class A ordinary shares), respectively. The Company raised a total of approximately US$213,850 in proceeds from this public offering, before deducting underwriting discounts and commissions and other issuance costs.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

12 Months Ended

Dec. 31, 2017

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,
	2015		2016		2017

Net revenue	30,598		846,168		1,469,929
Net (loss) income	(5,327	)	22,246		44,541
Net cash provided by operating activities	8,631		239,624		183,180
Net cash used in investing activities	(1,456	)	(158,681	)	(286,476	)
Net cash provided by (used in) financing activities	—		304,973		(28,092	)

Use of estimates

(b)Use of estimates

Cash and cash equivalents

(c)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, 2016 and 2017, 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, 2015		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
Additions		7,394
Accretion expense		949

Asset retirement obligations as of December 31, 2017		17,648

Intangible assets

(k)Intangible assets

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

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

Customer relationships		5-15 years
Favorable leases		20 years
Licenses		20 years

Licenses are amortized using a straight-line method over the estimated beneficial period.

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 RMB4,128, RMB8,942 and RMB10,189 in 2015, 2016 and 2017, respectively.

Start-up costs

(u)Start-up costs

Government grants

(v)Government grants

As of December 31, 2016 and 2017, deferred government grants of RMB14,051 and RMB16,789, respectively, 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 2015, 2016 and 2017 is as follows:

	Years ended December 31,
	2015		2016		2017

Total interest costs	138,260		324,085		466,460
Less: interest costs capitalized	(11,359	)	(58,851	)	(54,457	)

Interest expenses	126,901		265,234		412,003

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.

Unamortised debt issuance costs of RMB74,246 and RMB134,395 are presented as a reduction of debt as of December 31, 2016 and 2017, respectively.

Income tax

(y)Income tax

Share-based compensation

(z)Share-based compensation

For further information on share-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	446,621	34,437	—	—	—
In Hong Kong	12,350	189,632	27,126	10,630	158

Total in original currency	458,971	224,069	27,126	10,630	158

RMB equivalent	458,971	1,464,108	22,675	615	1,231

Concentration of credit risk

(cc)Concentration of credit risk

Earnings (loss) per share

(dd)Earnings (loss) per share

Recently Issued Accounting Standards

(ee)Recently Issued Accounting Standards

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2017

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,
	2015		2016		2017

Net revenue	30,598		846,168		1,469,929
Net (loss) income	(5,327	)	22,246		44,541
Net cash provided by operating activities	8,631		239,624		183,180
Net cash used in investing activities	(1,456	)	(158,681	)	(286,476	)
Net cash provided by (used in) financing activities	—		304,973		(28,092	)

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, 2015		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
Additions		7,394
Accretion expense		949

Asset retirement obligations as of December 31, 2017		17,648

Schedule of weighted-average amortization period of acquired intangible assets

Customer relationships		5-15 years
Favorable leases		20 years
Licenses		20 years

Schedule of reconciliation of total interest costs to interest expenses

	Years ended December 31,
	2015		2016		2017

Total interest costs	138,260		324,085		466,460
Less: interest costs capitalized	(11,359	)	(58,851	)	(54,457	)

Interest expenses	126,901		265,234		412,003

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

	RMB	USD	HKD	JPY	EUR
In PRC	446,621	34,437	—	—	—
In Hong Kong	12,350	189,632	27,126	10,630	158

Total in original currency	458,971	224,069	27,126	10,630	158

RMB equivalent	458,971	1,464,108	22,675	615	1,231

- 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 RECEIVABLE, NET (Tables)

12 Months Ended

Dec. 31, 2017

ACCOUNTS RECEIVABLE, NET

Schedule of accounts receivable, net

	As of December 31,
	2016	2017

Accounts receivable	198,851	364,654
Less: allowance for doubtful accounts	—	—

Accounts receivable, net	198,851	364,654

Schedule of allowance for doubtful accounts

	Years ended December 31,
	2015	2016		2017

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


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

OTHER CURRENT ASSETS (Tables)

12 Months Ended

Dec. 31, 2017

OTHER CURRENT ASSETS

Schedule of Other current assets

	As of December 31,
	2016	2017

Rental and other deposits	30,136	23,866
Assets held for sale	18,531	18,531
Others	484	254

	49,151	42,651

PROPERTY AND EQUIPMENT, NET (Tables)

12 Months Ended

Dec. 31, 2017

PROPERTY AND EQUIPMENT, NET

Schedule of property and equipment

	As of December 31, 2016		As of December 31, 2017

At cost:
Buildings	1,652,641		2,693,843
Data center equipment	1,349,069		2,202,247
Leasehold improvement	1,202,979		2,243,691
Furniture and office equipment	31,270		36,762
Vehicles	3,199		2,972

	4,239,158		7,179,515
Less: Accumulated depreciation	(613,658	)	(965,758	)

	3,625,500		6,213,757
Construction in progress	697,391		1,951,844

Property and equipment, net	4,322,891		8,165,601

Schedule of property and equipment under capital lease and other financing arrangement

	As of December 31, 2016		As of December 31, 2017

At cost (note):
Buildings	1,286,079		2,488,522
Data center equipment	26,375		192,946

	1,312,454		2,681,468
Less: Accumulated depreciation	(64,151	)	(141,948	)

	1,248,303		2,539,520

Schedule of depreciation of property and equipment

	Years ended December 31,
	2015	2016	2017

Cost of revenue	131,097	206,724	345,025
General and administrative expenses	4,767	5,425	6,902
Research and development expenses	—	724	553

	135,864	212,873	352,480

INTANGIBLE ASSETS, NET (Tables)

12 Months Ended

Dec. 31, 2017

INTANGIBLE ASSETS, NET

Schedule of Intangible assets

	Note	As of December 31, 2016		As of December 31, 2017

Customer relationships	8	104,322		379,322
Favorable leases	8	15,500		15,500
Licenses		—		6,000

		119,822		400,822
Less: accumulated amortization		(27,253	)	(52,356	)

Intangible assets, net		92,569		348,466

Schedule of Estimated future amortization expense

Fiscal year ending December 31,
2018		37,829
2019		37,829
2020		29,680
2021		29,680
2022		29,680
Thereafter		183,768

Total		348,466

PREPAID LAND USE RIGHTS (Tables)

12 Months Ended

Dec. 31, 2017

PREPAID LAND USE RIGHTS

Schedule of prepaid land use rights

	As of December 31,
	2016		2017

Prepaid land use rights	28,370		28,370
Less: Accumulated amortization	(1,578	)	(2,125	)

Prepaid land use rights, net	26,792		26,245

BUSINESS COMBINATIONS (Tables)

12 Months Ended

Dec. 31, 2017

BUSINESS COMBINATIONS

Schedule of movement of goodwill

	As of December 31,
	2016	2017

Balance at the beginning of the year	1,294,664	1,341,087
Addition during the year	46,423	229,668

Balance at end of year	1,341,087	1,570,755

Weiteng Construction/Guangzhou 1

BUSINESS COMBINATIONS

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, in February and May 2016, the Company lent short-term loans of RMB40,000 and RMB2,000, respectively, to Weiteng Construction. 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 Weiteng Construction. At the acquisition date, the amount due from Weiteng Construction of RMB43,161, 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. 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 Weiteng Construction 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.

Target Group, Shenzhen 5

BUSINESS COMBINATIONS

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

	Note
Fair value of consideration	(i)	294,491
Effective settlement of pre-existing relationships upon consolidation	(ii)	6,025
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash		(11,153	)
Property and equipment	(iii)	(821,405	)
Identifiable intangible assets	(iv)	(176,500	)
Other assets		(59,520	)
Accounts payable		219,207
Capital lease and other financing obligations, current		23,156
Capital lease and other financing obligations, non-current		363,380
Long-term borrowings		217,790
Deferred tax liabilities		45,931
Other liabilities		55,299

Total identifiable net assets		(143,815	)

Goodwill	(v)	156,701

Note (i):	The fair value of consideration represents the present value of the purchase price of RMB312,000, of which RMB69,832 was paid up to December 31, 2017. As of December 31, 2017, total consideration payable for the acquisition was RMB230,539. The payment schedule of remaining consideration is based on the milestone related to the achievement of all specified conditions. RMB109,658 and RMB120,881 were recorded in other payables and other long-term liabilities, respectively as of December 31, 2017.

Note (ii):	Prior to the acquisition, the Company had other receivables from the target group of RMB6,025, which was effectively settled with the seller upon completion of the acquisition.

Note (iii):	Property and equipment acquired included properties and equipment acquired under capital lease and other financing arrangement of RMB416,000, data center equipment of RMB174,292, leasehold improvements of RMB118,368 and construction in progress of RMB112,745.

Note (iv):	Identifiable intangible assets acquired consisted of customer relationships of RMB176,500 with an estimated useful life of 14.4 years.

Note (v):	Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in the acquisition. 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 the target group 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 ASC 350, goodwill is not amortized but is tested for impairment.

Target Group Guangzhou 2

BUSINESS COMBINATIONS

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

	Note
Fair value of consideration		233,984
Effective settlement of pre-existing relationships upon consolidation	(i)	(1,807	)
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash		(10,144	)
Accounts receivable		(25,177	)
Property and equipment	(ii)	(319,943	)
Identifiable intangible assets	(iii)	(98,500	)
Other assets		(14,135	)
Accounts payable		56,431
Capital lease and other financing obligations, current		5,958
Capital lease and other financing obligations, non-current		101,875
Short-term borrowings		50,750
Long-term borrowings		52,999
Deferred tax liabilities		35,097
Other liabilities		5,579

Total identifiable net assets		(159,210	)

Goodwill	(iv)	72,967

Note (i):	Prior to the acquisition, the Company had payables to the target group of RMB1,807, which was effectively settled with the seller upon completion of the acquisition.

Note (ii):	Property and equipment acquired included properties and equipment acquired under capital lease and other financing arrangement of RMB106,000, data center equipment of RMB57,932, leasehold improvement of RMB155,149 and furniture and office equipment of RMB862.

Note (iii):	Identifiable intangible assets acquired consisted of customer relationships of RMB98,500 with an estimated useful life of 11.8 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. 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 the target group 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 ASC 350, goodwill is not amortized but is tested for impairment.

OTHER NON-CURRENT ASSETS (Tables)

12 Months Ended

Dec. 31, 2017

OTHER NON-CURRENT ASSETS

Schedule of other non-current assets

	As of December 31,
	2016	2017

Rental and other deposits	77,985	193,626
Others	20,740	18,159

	98,725	211,785

LOANS AND BORROWINGS (Tables)

12 Months Ended

Dec. 31, 2017

LOANS AND BORROWINGS

Schedule of borrowings

	As of December 31, 2016	As of December 31, 2017

Short-term borrowings	239,777	462,946
Current portion of long-term borrowings	388,701	327,538

Sub-total	628,478	790,484
Long-term borrowings, excluding current portion	1,509,676	3,459,765

Total loans and borrowings	2,138,154	4,250,249

Schedule of short-term borrowings

	As of December 31, 2016	As of December 31, 2017

Unsecured short-term loans and borrowings	—	230,000
Secured short-term loans and borrowings	239,777	232,946


	239,777	462,946

Schedule of assets to secure the short-term borrowings

	As of December 31, 2016	As of December 31, 2017

Accounts receivable	19,914	11,615

Schedule of long-term borrowings

	As of December 31, 2016	As of December 31, 2017

Unsecured long-term loans and borrowings	—	167,250
Secured long-term loans and borrowings	1,898,377	3,620,053

	1,898,377	3,787,303

Schedule of assets to secure the long-term borrowings

	As of December 31, 2016	As of December 31, 2017

Accounts receivable	67,433	124,428
Property and equipment, net	512,566	698,922
Prepaid land use rights, net	20,735	6,091

	600,734	829,441

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

Twelve-months ending December 31 ,		Long-term borrowings
2018		327,538
2019		571,091
2020		839,502
2021		1,022,698
2022		715,457
Thereafter		311,017

		3,787,303

- 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=84159872&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=75038535&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=84159872&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=84159872&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=84159872&loc=d3e21521-112644

+ Details

ACCRUED EXPENSES AND OTHER PAYABLES (Tables)

12 Months Ended

Dec. 31, 2017

ACCRUED EXPENSES AND OTHER PAYABLES

Summary of Accrued expenses and other payables

	As of December 31,
	2016	2017

Accrued interest expenses	67,324	21,114
Accrued debt issuance costs	—	34,194
Income tax payable (note 20)	15,265	20,122
Consideration payables for acquisitions (note 8)	25,900	159,489
Other accrued expenses	71,924	101,275
Other payables	27,537	32,430

	207,950	368,624

LEASE (Tables)

12 Months Ended

Dec. 31, 2017

LEASE

Schedule of capital lease and other financing obligations

	December 31, 2016						December 31, 2017
	Capital lease obligations		Other financing obligations		Total		Capital lease obligations		Other financing obligations		Total
Within 1 year	71,300		22,044		93,344		212,780		45,007		257,787
After 1 year but within 2 years	85,783		38,443		124,226		220,293		63,151		283,444
After 2 years but within 3 years	92,677		39,548		132,225		316,475		75,685		392,160
After 3 years but within 4 years	193,202		41,586		234,788		144,052		76,678		220,730
After 4 years but within 5 years	71,501		42,287		113,788		141,910		80,832		222,742
After 5 years	716,089		725,178		1,441,267		1,900,744		1,469,318		3,370,062

Total	1,230,552		909,086		2,139,638		2,936,254		1,810,671		4,746,925

Less total future interest	(552,060	)	(450,670	)	(1,002,730	)	(1,209,120	)	(905,590	)	(2,114,710	)
Less: estimated building costs	—		(25,356	)	(25,356	)	—		(231,228	)	(231,228	)

Present value of lease and other financing obligations	678,492		433,060		1,111,552		1,727,134		673,853		2,400,987

Including:
Current portion					88,593						97,943

Non-current portion					1,022,959						2,303,044

Schedule of Future minimum operating lease payments

Twelve-months ending December 31,
2018		135,599
2019		101,152
2020		88,587
2021		48,939
2022		48,723
Thereafter		337,355

Total		760,355

OTHER LONG-TERM LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2017

OTHER LONG-TERM LIABILITIES

Schedule of other long-term liabilities

	As of December 31, 2016	As of December 31, 2017

Consideration payable for an acquisition (Note 8)	—	120,881
Payables for purchase of property and equipment	37,126	195,749
Accrued interests	51,112	—
Deferred government grants	14,051	16,789
Others	9,417	25,479

Total	111,706	358,898

REDEEMABLE PREFERRED SHARES (Tables)

12 Months Ended

Dec. 31, 2017

REDEEMABLE PREFERRED SHARES

Schedule of movement of the redeemable preferred shares

	Series A				Series A*				Series B				Series B1				Series B2				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
Balance at 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, 2017

SHARE-BASED COMPENSATION

Summary of the share option activities

				Weighted
				average
			Weighted	grant-date
	Number		average	fair value
	of options		exercise price	per option
			(RMB)	(RMB)
Options outstanding at January 1, 2015	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

Granted	333,334		5.2	10.6
Exercised	(816,880	)	5.3	1.9
Forfeited	(19,000	)	5.3	1.9

Options outstanding at December 31, 2017	28,087,236		5.1	3.2


Options vested and expect to vest at December 31, 2017	28,087,236		5.1	3.2

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

		Weighted
		average	Weighted
	Number	remaining	average
	of shares	contractual life	exercise price
		(years)	(RMB)
Options outstanding and exercisable	28,087,236	2.2	5.1

Assumptions used to estimate fair value of stock options

Grant date:	January 2015	May 2016
Risk-free rate of return	2.27%	1.98%
Volatility	29.80%	28.50%
Expected dividend yield	—	—
Exercise multiple	2.20	2.20
Fair value of underlying ordinary share	US$0.90	US$1.51
	(RMB 5.5)	(RMB 9.8)
Expected term	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
Granted	13,977,060		5.2
Vested	(2,123,120	)	8.5
Forfeited	(238,400	)	6.8

Unvested at December 31, 2017	24,525,620		5.3

Summary of share-based compensation expenses

	Years ended December 31,
	2015	2016	2017

Costs of revenue	484	2,114	9,941
Selling and marketing expenses	325	6,590	18,390
General and administrative expenses	3,252	55,409	30,866
Research and development expenses	—	52	646

Total share-based compensation expenses	4,061	64,165	59,843

Restricted shares

SHARE-BASED COMPENSATION

Assumptions used to estimate fair value of the restricted shares

Grant date:	December 2016	July 2017
Risk-free rate of return	0.68 - 1.65%	1.29 - 1.63%
Volatility	22.35 - 24.80%	20.43 - 21.48%
Expected dividend yield	—	—
Share price at grant date	US$1.24	US$1.191
	(RMB8.6)	(RMB8.0)
Expected term	1 - 5 years	2 - 4 years

REVENUE (Tables)

12 Months Ended

Dec. 31, 2017

REVENUE

Schedule of Net revenue

	Years ended December 31,
	2015	2016	2017

Service revenue	653,591	1,003,015	1,591,860
Equipment sales	50,045	52,945	24,306

	703,636	1,055,960	1,616,166

INCOME TAX (Tables)

12 Months Ended

Dec. 31, 2017

INCOME TAX

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

	Years ended December 31,
	2015		2016		2017
Loss before income taxes:
PRC	94,190		144,158		130,961
Other jurisdictions	16,377		140,569		202,015
Total loss before income taxes	110,567		284,727		332,976


Current tax expenses:
PRC	(1,650	)	311		5,546
Other jurisdictions	256		1,998		—

Total current tax (benefits) expenses	(1,394	)	2,309		5,546


Deferred tax benefits:
PRC	(10,589	)	(10,935	)	(11,683	)
Other jurisdictions	—		311		61


Total deferred tax benefits	(10,589	)	(10,624	)	(11,622	)



Total income taxes benefits	(11,983	)	(8,315	)	(6,076	)

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

	Years ended December 31,
	2015		2016		2017

PRC enterprise income tax rate	25.0	%	25.0	%	25.0	%
Non-PRC entities not subject to income tax	(3.8	)%	(13.7	)%	(14.8	)%
Tax differential for entities in non-PRC jurisdiction	0.0	%	0.5	%	(0.8	)%
Tax effect of permanent differences	(0.6	)%	(0.3	)%	0.0	%
Change in valuation allowance	(9.4	)%	(8.4	)%	(7.8	)%
Return to provision adjustment	(0.4	)%	(0.2	)%	0.2	%


	10.8	%	2.9	%	1.8	%

Schedule of components of deferred tax assets and liabilities

	As of December 31,
	2016		2017
Deferred tax assets:
Government subsidy	3,763		4,197
Accrued expenses	23,324		14,024
Asset retirement obligation	2,377		4,412
Net operating loss carry forwards	141,749		170,267
Total gross deferred tax assets	171,213		192,900
Valuation allowance on deferred tax assets	(134,935	)	(152,241	)

Deferred tax assets, net of valuation allowance	36,278		40,659


Deferred tax liabilities:
Property and equipment	(36,644	)	(52,417	)
Intangible assets	(22,914	)	(82,305	)
Prepaid land use rights	(1,733	)	(1,693	)
Obligation under capital lease and other financing obligations	(15,641	)	(14,216	)

Total deferred tax liabilities	(76,932	)	(150,631	)


Net deferred tax liabilities	(40,654	)	(109,972	)


Analysis as:
Deferred tax assets	12,626		14,305
Deferred tax liabilities	(53,280	)	(124,277	)

Net deferred tax liabilities	(40,654	)	(109,972	)

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

	Years ended December 31,
	2015	2016	2017

Balance at the beginning of the year	116,403	118,952	134,935
Increase during the year	2,549	15,983	17,306

Balance at the end of the year	118,952	134,935	152,241

LOSS PER ORDINARY SHARE (Tables)

12 Months Ended

Dec. 31, 2017

LOSS PER ORDINARY SHARE

Schedule of computation of basic and diluted loss per share

	Years ended December 31,
	2015		2016		2017

Net loss	98,584		276,412		326,900

Change in redemption value of redeemable preferred shares (i)	110,926		(205,670	)	—
(Cumulative) Dividend on preferred shares (ii)	7,127		332,660		—

Net loss attributable to ordinary shareholders	216,637		403,402		326,900


Weighted average number of ordinary shares outstanding-basic and diluted (iii)	217,987,922		299,093,937		784,566,371

Loss per ordinary share - basic and diluted	(0.99	)	(1.35	)	(0.42	)

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 (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 year ended December 31, 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 (note 15) upon the IPO less the cumulative dividend on preferred shares amounting to RMB7,127 for the year ended December 31, 2015.

Note (iii):	During the year ended December 31, 2017, the Company issued 20,000,000 ordinary shares to its share depository bank which have been and will continue to be used to settle stock option and restricted share awards upon their exercise. No consideration was received by the Company for this issuance of ordinary shares. These ordinary shares are legally issued and outstanding but are treated as escrowed shares for accounting purposes and, therefore, have been excluded from the computation of loss per ordinary share. Any ordinary shares not used in the settlement of stock option and restricted share awards will be returned to the Company.

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

	Years ended December 31,
	2015	2016	2017

Share options/restricted shares	17,193,534	41,499,862	52,612,856
Convertible bonds payable	59,692,156	93,977,837	—
Redeemable preferred shares	349,087,677	—	—

Total	425,973,367	135,477,699	52,612,856

COMMITMENTS (Tables)

12 Months Ended

Dec. 31, 2017

COMMITMENTS

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

	As of December 31, 2016	As of December 31, 2017

Contracted for	510,999	1,065,551

RELATED PARTY TRANSACTIONS (Tables)

12 Months Ended

Dec. 31, 2017

RELATED PARTY TRANSACTIONS

Schedule of material related party relationship

In 2015, 2016 and 2017, the related parties of the Company are as follows:

Name of party		Relationship

William Wei Huang (Mr. Huang)		Director and CEO of the Company
STT GDC		Principal ordinary shareholder of the Company
Global Data Solutions Ltd.		Principal ordinary shareholder of the Company
SBCVC Holdings Limited (“SBCVC”)		Principal ordinary shareholder of the Company

Schedule of major transactions with related parties

		Years ended December 31,
		2015	2016	2017

Preference dividends
STT GDC	(i)	—	223,225	—
SBCVC		—	109,665	—
Other non-principal preferred shareholders		—	10,406	—

		—	343,296	—


Loan from a related party	(ii)	64,936	—	—


Repayment of a related party loan	(ii)	—	65,474	—


Convertible bonds from a related party	(ii)	—	327,580	—


Conversion of convertible bonds from a related party	(ii)	—	—	366,958


Interest expenses
STT GDC	(ii)	2,579	32,245	30,078

Note (i):	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.

Note (ii):	During the year ended December 31, 2015, the Company borrowed a loan of US$10,000 (RMB64,936) from STT GDC. The interest expenses on the loan amounted to US$397(RMB2,579).

	On January 29, 2016, the Company received the second tranche of US$50,000 (RMB327,580) from STT GDC 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 years ended December 31, 2016 and 2017, the related interest expense arising from the Convertible Bonds due 2019 subscribed by STT GDC amounted to RMB32,245 and RMB30,078, respectively.

	In November 2017, the Convertible Bonds due 2019 and the Accrued Interest thereon due to STT GDC were fully converted into 32,540,515 newly issued Class A ordinary shares at the conversion price of $1.675262. In addition, upon conversion, the accrued but unpaid Cash Interest due to STT GDC of RMB4,991 was relinquished.

PARENT ONLY FINANCIAL INFORMATION (Tables)

12 Months Ended

Dec. 31, 2017

Parent Company

Schedule of condensed financial statements

Condensed Balance Sheets

	As of December 31,
	2016		2017
Assets

Current assets
Cash	1,030,627		999,194
Prepaid expenses	1,011		6,295
Total current assets	1,031,638		1,005,489
Investment and loans to subsidiaries	3,054,835		3,477,331
Other non-current assets	15,856		14,936
Total assets	4,102,329		4,497,756

Liabilities and Shareholders’ Equity

Current liabilities
Accounts payable	—		3,597
Accrued expenses and other payables	23,266		9,973
Due to subsidiaries	927		843
Total current liabilities	24,193		14,413

Convertible bonds payable	1,040,550		—
Other long-term liabilities	51,112		7,831
Total liabilities	1,115,855		22,244

Shareholders’ equity
Ordinary shares (US$0.00005 par value; 2,002,000,000 shares authorized; 760,009,043 and 941,269,679 shares issued and outstanding as of December 31, 2016 and 2017, respectively)	260		320
Additional paid-in capital	4,036,959		5,861,445
Accumulated other comprehensive loss	(192,080	)	(200,688	)
Accumulated deficit	(858,665	)	(1,185,565	)

Total shareholders’ equity	2,986,474		4,475,512

Commitments and contingencies

Total liabilities and shareholders’ equity	4,102,329		4,497,756

Condensed Statements of Operations

	Years ended December 31,
	2015		2016		2017

Net revenue	—		—		—
Cost of revenue	—		(2,381	)	(10,392	)

Gross loss	—		(2,381	)	(10,392	)

Operating expenses
Selling and marketing expenses	(1,566	)	(8,914	)	(22,528	)
General and administrative expenses	(14,665	)	(82,794	)	(59,500	)
Research and development expenses	—		(52	)	(646	)

Loss from operations	(16,231	)	(94,141	)	(93,066	)

Other income (expenses):
Interest income	—		16		3,901
Interest expenses	(3,297	)	(97,603	)	(90,408	)
Equity in loss of subsidiaries	(79,056	)	(84,952	)	(147,340	)
Others, net	—		268		13

Loss before income taxes	(98,584	)	(276,412	)	(326,900	)

Income tax expenses	—		—		—

Net loss	(98,584	)	(276,412	)	(326,900	)

Condensed Statements of Comprehensive Loss

	Years ended December 31,
	2015		2016		2017

Net loss	(98,584	)	(276,412	)	(326,900	)
Other comprehensive loss:
Foreign currency translation adjustments, net of nil tax	(118,491	)	(130,131	)	(8,608	)

Comprehensive loss	(217,075	)	(406,543	)	(335,508	)

Condensed Statements of Cash Flows

	Years ended December 31,
	2015		2016		2017

Operating activities:
Net cash used in operating activities	(4,895	)	(62,591	)	(58,068	)

Investing activities
Deposit paid for a potential acquisition	—		(15,000	)	—
Increase of due from subsidiaries	(93,101	)	(990,617	)	(588,768	)

Net cash used in investing activities	(93,101	)	(1,005,617	)	(588,768	)


Financing activities:
Proceeds from exercise of stock options	—		—		3,377
Proceeds from issuance of convertible bonds	648,950		327,580		—
Repayment of bonds payable	(14,330	)	—		—
Proceeds from a related party loan	64,936		—		—
Repayment of a related party loan	—		(65,474	)	—
Net proceeds from issuance of ordinary shares	—		1,221,518		649,834
Payment of preferred shares dividends	—		(76,502	)	—
Repurchase of redeemable preferred shares	(23,300	)	—		—

Net cash provided by financing activities	676,256		1,407,122		653,211
Effect of exchange rate changes on cash	57,565		47,787		(37,808	)


Net increase (decrease) in cash	635,825		386,701		(31,433	)
Cash at beginning of year	8,101		643,926		1,030,627

Cash at end of year	643,926		1,030,627		999,194


Supplemental disclosures of cash flow information
Interest paid	3,463		45,495		33,920

Supplemental disclosures of non-cash investing and financing activities
Issuance of ordinary shares to settle preference dividend	—		266,794		—
Conversion of convertible bonds	—		—		1,106,227

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
VIEs financial information
Net revenue	¥ 1,616,166	¥ 1,055,960	¥ 703,636
Net (loss) income	(326,900)	(276,412)	(98,584)
Net cash provided by operating activities	(174,612)	(150,228)	(80,298)
Net cash used in investing activities	(2,035,778)	(1,147,064)	(731,905)
Net cash provided by (used in) financing activities	2,346,767	2,128,614	1,127,685
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	¥ 1,469,929	846,168	30,598
Net (loss) income	44,541	22,246	(5,327)
Net cash provided by operating activities	183,180	239,624	8,631
Net cash used in investing activities	(286,476)	(158,681)	(1,456)
Net cash provided by (used in) financing activities	(28,092)	304,973
Costs for outsourcing and other services provided by other entities within the Company	¥ 658,617	¥ 343,271	¥ 7,506

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property and equipment (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property and equipment
Depreciation	¥ 352,480	¥ 212,873	¥ 135,864
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, 2017	Dec. 31, 2016	Dec. 31, 2015
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, 2017	Dec. 31, 2016	Dec. 31, 2015
Activity of the asset retirement obligation liability
Asset retirement obligations at beginning of the period	¥ 9,305	¥ 5,775	¥ 2,221
Additions	7,394	2,942	3,299
Accretion expense	949	588	255
Asset retirement obligations at end of the period	¥ 17,648	¥ 9,305	¥ 5,775

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Intangible assets (Details)	12 Months Ended
	Dec. 31, 2017
Customer relationships \| Minimum
Intangible assets
Weighted-average amortization period (in years)	5 years
Customer relationships \| Maximum
Intangible assets
Weighted-average amortization period (in years)	15 years
Favorable leases
Intangible assets
Weighted-average amortization period (in years)	20 years
Licenses
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, 2017
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, 2017	Dec. 31, 2016	Dec. 31, 2015
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, 2017	Dec. 31, 2016	Dec. 31, 2015
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, 2017	Dec. 31, 2016
Value-added-tax ("VAT")
Value-added-tax ("VAT") recoverable	¥ 112,067	¥ 72,958
VAT recoverable	290,065	98,863
Accrued expenses and other payables
Value-added-tax ("VAT")
VAT payables	¥ 11,213	¥ 5,954

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue recognition (Details)	12 Months Ended
	Dec. 31, 2017
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	10 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, 2017	Dec. 31, 2016	Dec. 31, 2015
Research and development and advertising costs
Research and development expenses	¥ 7,261	¥ 9,100	¥ 3,554
Advertising costs	10,189	8,942	4,128
Capitalized interest
Total interest costs	466,460	324,085	138,260
Less: interest costs capitalized	(54,457)	(58,851)	(11,359)
Interest expenses	412,003	265,234	126,901
Debt issuance cost
Unamortised debt issuance costs	134,395	74,246
Other long-term liabilities
Government grants
Deferred government grants	16,789	14,051
General and administrative expenses
Start-up costs
Pre-operating or start-up costs incurred prior to operating a new data center	¥ 7,469	¥ 12,976	¥ 25,659

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Employee benefits (Details)	12 Months Ended
	Dec. 31, 2017
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, 2017 USD ($)	Dec. 31, 2017 JPY (¥)	Dec. 31, 2017 HKD ($)	Dec. 31, 2017 EUR (€)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
RMB
Cash and restricted cash					¥ 458,971	¥ 501,125
USD
Cash and restricted cash	$ 224,069				1,464,108
HKD
Cash and restricted cash			$ 27,126		22,675
JPY
Cash and restricted cash		¥ 10,630			615
EUR
Cash and restricted cash				€ 158	1,231
PRC \| RMB
Cash and restricted cash					446,621
PRC \| USD
Cash and restricted cash \| $	34,437
Hong Kong \| RMB
Cash and restricted cash					¥ 12,350
Hong Kong \| USD
Cash and restricted cash \| $	$ 189,632
Hong Kong \| HKD
Cash and restricted cash \| $			$ 27,126
Hong Kong \| JPY
Cash and restricted cash		¥ 10,630
Hong Kong \| EUR
Cash and restricted cash \| €				€ 158

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recently Issued Accounting Standards (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Future minimum lease payments	¥ 760,355
ASU 2016-18
Restricted cash	¥ 74,154	¥ 27,673
ASU 2016-02
Operating lease commitments expiration period	20 years
Future minimum lease payments	¥ 760,355

ACCOUNTS RECEIVABLE, NET (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
ACCOUNTS RECEIVABLE, NET (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Accounts receivable
Accounts receivable	¥ 198,851		¥ 364,654
Accounts receivable, net	198,851		364,654
Unbilled portion	117,192		253,724
Movement of the allowance for doubtful accounts
Balance at the beginning of the year	2,156	¥ 2,156
Reversal during the year	(2,156)
Balance at the end of the year		¥ 2,156
Accounts receivable
Accounts receivable
Assets pledged	¥ 87,347		¥ 136,043

OTHER CURRENT ASSETS (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other current assets
Rental and other deposits	¥ 23,866	¥ 30,136
Assets held for sale	18,531	18,531
Others	254	484
Total other current assets	42,651	¥ 49,151
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, 2017	Dec. 31, 2016
At cost:
Property and equipment, gross	¥ 7,179,515	¥ 4,239,158
Less: Accumulated depreciation	(965,758)	(613,658)
Property and equipment net excluding construction in process	6,213,757	3,625,500
Construction in progress	1,951,844	697,391
Property and equipment, net	8,165,601	4,322,891
Buildings
At cost:
Property and equipment, gross	2,693,843	1,652,641
Data center equipment
At cost:
Property and equipment, gross	2,202,247	1,349,069
Leasehold improvement
At cost:
Property and equipment, gross	2,243,691	1,202,979
Furniture and office equipment
At cost:
Property and equipment, gross	36,762	31,270
Vehicles
At cost:
Property and equipment, gross	¥ 2,972	¥ 3,199

PROPERTY AND EQUIPMENT, NET - Acquired under capital leases (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
At cost:
Capital leased assets, gross	¥ 2,681,468	¥ 1,312,454
Less: Accumulated depreciation	(141,948)	(64,151)
Capital leases, balance sheet, Assets by major class, net, total	2,539,520	1,248,303
Buildings
At cost:
Capital leased assets, gross	2,488,522	1,286,079
Buildings under construction
At cost:
Capital leased assets, gross	476,489	313,721
Data center equipment
At cost:
Capital leased assets, gross	192,946	26,375
Data center equipment under construction
At cost:
Capital leased assets, gross	¥ 180,228	¥ 0

PROPERTY AND EQUIPMENT, NET - Depreciation (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Depreciation expense
Depreciation of property and equipment	¥ 352,480	¥ 212,873	¥ 135,864
Cost of revenue
Depreciation expense
Depreciation of property and equipment	345,025	206,724	131,097
General and administrative expenses
Depreciation expense
Depreciation of property and equipment	6,902	5,425	¥ 4,767
Research and development expenses
Depreciation expense
Depreciation of property and equipment	¥ 553	¥ 724

PROPERTY AND EQUIPMENT, NET - Other information (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
PROPERTY AND EQUIPMENT, NET
Payables for purchase of property and equipment due beyond one year	¥ 195,749	¥ 37,126
Property and equipment, net
PROPERTY AND EQUIPMENT, NET
Net book value of an asset pledged as security for bank loans	¥ 698,922	¥ 512,566

INTANGIBLE ASSETS, NET (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
INTANGIBLE ASSETS, NET (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Intangible assets
Intangible assets, gross	¥ 400,822	¥ 119,822
Less: accumulated amortization	(52,356)	(27,253)
Intangible assets, net	348,466	92,569
Amortization of intangible assets	25,103	13,866	¥ 8,925
Estimated future amortization expense
2018	37,829
2019	37,829
2020	29,680
2021	29,680
2022	29,680
Thereafter	183,768
Intangible assets, net	348,466	92,569
Customer relationships
Intangible assets
Intangible assets, gross	379,322	104,322
Favorable leases
Intangible assets
Intangible assets, gross	15,500	¥ 15,500
Licenses
Intangible assets
Intangible assets, gross	¥ 6,000

PREPAID LAND USE RIGHTS (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
PREPAID LAND USE RIGHTS (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Prepaid land use rights	¥ 28,370	¥ 28,370
Less: Accumulated amortization	(2,125)	(1,578)
Prepaid land use rights, net	26,245	26,792
Amortization of prepaid land use rights	547	616	¥ 617
Prepaid land use rights
Net book value of an asset pledged as security for bank loans	¥ 6,091	¥ 20,735

BUSINESS COMBINATIONS - Movement of goodwill (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Movement of goodwill
Balance at the beginning of the year	¥ 1,341,087	¥ 1,294,664
Addition during the year	229,668	46,423
Balance at end of year	¥ 1,570,755	¥ 1,341,087

BUSINESS COMBINATIONS - Assets acquired (Details) - CNY (¥) ¥ in Thousands				1 Months Ended		3 Months Ended	6 Months Ended	7 Months Ended	12 Months Ended
	Oct. 09, 2017	Jun. 29, 2017	May 19, 2016	May 31, 2016	Feb. 29, 2016	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
The identifiable assets acquired and liabilities assumed in the business combination
Consideration paid									¥ 279,885	¥ 103,600
Recognized amounts of identifiable assets acquired and liabilities assumed
Goodwill						¥ 1,570,755	¥ 1,570,755	¥ 1,341,087	1,570,755	1,341,087	¥ 1,294,664
Net revenue									1,616,166	1,055,960	703,636
Net (loss) income									(326,900)	¥ (276,412)	¥ (98,584)
Weiteng Construction/Guangzhou 1
The identifiable assets acquired and liabilities assumed in the business combination
Fair value of consideration transferred			¥ 129,500
Consideration paid				¥ 103,600					25,900
Effective settlement of pre-existing relationships upon consolidation			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 Weiteng Construction			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 Weiteng Construction, including interest receivable			43,161
Interest receivable			1,161
Net revenue								36,924
Net (loss) income								¥ (2,861)
Weiteng Construction/Guangzhou 1 \| Capital lease
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(102,785)
Weiteng Construction/Guangzhou 1 \| Data center equipment
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(19,895)
Weiteng Construction/Guangzhou 1 \| Leasehold improvement
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(132,462)
Weiteng Construction/Guangzhou 1 \| Construction in progress
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment			(26,295)
Target Group, Shenzhen 5
The identifiable assets acquired and liabilities assumed in the business combination
Fair value of consideration transferred		¥ 294,491
Consideration paid							69,832
Contingent consideration		312,000				230,539	230,539		230,539
Effective settlement of pre-existing relationships upon consolidation		6,025
Recognized amounts of identifiable assets acquired and liabilities assumed
Cash		(11,153)
Property and equipment		(821,405)
Identifiable intangible assets		(176,500)
Other assets		(59,520)
Accounts payable		219,207
Capital lease and other financing obligations, current		23,156
Capital lease and other financing obligations, non-current		363,380
Long-term borrowings		217,790
Deferred tax liabilities		45,931
Other liabilities		55,299
Total identifiable net assets		(143,815)
Goodwill		156,701
Net revenue							42,072
Net (loss) income							(23,859)
Target Group, Shenzhen 5 \| Other payables
The identifiable assets acquired and liabilities assumed in the business combination
Contingent consideration						109,658	109,658		109,658
Target Group, Shenzhen 5 \| Other long-term liabilities
The identifiable assets acquired and liabilities assumed in the business combination
Contingent consideration						120,881	¥ 120,881		¥ 120,881
Target Group, Shenzhen 5 \| Capital lease
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment		(416,000)
Target Group, Shenzhen 5 \| Data center equipment
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment		(174,292)
Target Group, Shenzhen 5 \| Leasehold improvement
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment		(118,368)
Target Group, Shenzhen 5 \| Construction in progress
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment		(112,745)
Target Group Guangzhou 2
The identifiable assets acquired and liabilities assumed in the business combination
Fair value of consideration transferred	¥ 233,984
Consideration paid						184,153
Effective settlement of pre-existing relationships upon consolidation	(1,807)
Recognized amounts of identifiable assets acquired and liabilities assumed
Cash	(10,144)
Accounts receivable	(25,177)
Property and equipment	(319,943)
Identifiable intangible assets	(98,500)
Other assets	(14,135)
Accounts payable	56,431
Capital lease and other financing obligations, current	5,958
Capital lease and other financing obligations, non-current	101,875
Short-term borrowings	50,750
Long-term borrowings	52,999
Deferred tax liabilities	35,097
Other liabilities	5,579
Total identifiable net assets	(159,210)
Goodwill	72,967
Net revenue						26,573
Net (loss) income						¥ 2,734
Target Group Guangzhou 2 \| Capital lease
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment	(106,000)
Target Group Guangzhou 2 \| Data center equipment
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment	(57,932)
Target Group Guangzhou 2 \| Leasehold improvement
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment	(155,149)
Target Group Guangzhou 2 \| Furniture and office equipment
Recognized amounts of identifiable assets acquired and liabilities assumed
Property and equipment	(862)
Consolidation eliminations \| Target Group, Shenzhen 5
The identifiable assets acquired and liabilities assumed in the business combination
Effective settlement of pre-existing relationships upon consolidation		6,025
Consolidation eliminations \| Target Group Guangzhou 2
The identifiable assets acquired and liabilities assumed in the business combination
Effective settlement of pre-existing relationships upon consolidation	1,807
Customer relationships \| Weiteng Construction/Guangzhou 1
Recognized amounts of identifiable assets acquired and liabilities assumed
Identifiable intangible assets			¥ (59,500)
Customer relationships \| Target Group, Shenzhen 5
Recognized amounts of identifiable assets acquired and liabilities assumed
Identifiable intangible assets		¥ (176,500)
Estimated useful life (in years)		14 years 4 months 24 days
Customer relationships \| Target Group Guangzhou 2
Recognized amounts of identifiable assets acquired and liabilities assumed
Identifiable intangible assets	¥ (98,500)
Estimated useful life (in years)	11 years 9 months 18 days
Minimum \| Customer relationships \| Weiteng Construction/Guangzhou 1
Recognized amounts of identifiable assets acquired and liabilities assumed
Estimated useful life (in years)			7 years
Maximum \| Customer relationships \| Weiteng Construction/Guangzhou 1
Recognized amounts of identifiable assets acquired and liabilities assumed
Estimated useful life (in years)			8 years

OTHER NON-CURRENT ASSETS (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
OTHER NON-CURRENT ASSETS
Rental and other deposits	¥ 193,626	¥ 77,985
Others	18,159	20,740
Total other non-current assets	¥ 211,785	¥ 98,725

LOANS AND BORROWINGS - Total loans and borrowings (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans and borrowings
Short-term borrowings	¥ 462,946	¥ 239,777
Current portion of long-term borrowings	327,538	388,701
Sub-total	790,484	628,478
Long-term borrowings, excluding current portion	3,459,765	1,509,676
Total loans and borrowings	¥ 4,250,249	¥ 2,138,154

LOANS AND BORROWINGS - Type of short-term borrowings (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Short-term borrowings by type
Unsecured short-term loans and borrowings	¥ 230,000
Secured short-term loans and borrowings	232,946	¥ 239,777
Short-term borrowings	¥ 462,946	¥ 239,777

LOANS AND BORROWINGS - Short-term borrowings secured (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Short-term borrowings
Weighted average interest rates of short-term borrowings	7.93%	5.27%
Accounts receivable
Short-term borrowings
Assets to secure short-term loans and borrowings	¥ 11,615	¥ 19,914

LOANS AND BORROWINGS - Long-term borrowings (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Long-term borrowings by type
Unsecured long-term loans and borrowings	¥ 167,250
Secured long-term loans and borrowings	3,620,053	¥ 1,898,377
Long-term borrowings	¥ 3,787,303	¥ 1,898,377
Weighted average interest rates of long-term borrowings	6.93%	8.16%

LOANS AND BORROWINGS - Long-term borrowings secured (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans and Borrowings
Assets to secure long-term loans and borrowings	¥ 829,441	¥ 600,734
Long-term loans guaranteed by William Wei Huang, Director and CEO of the Company	0	9,500
Accounts receivable
Loans and Borrowings
Assets to secure long-term loans and borrowings	124,428	67,433
Property and equipment, net
Loans and Borrowings
Assets to secure long-term loans and borrowings	698,922	512,566
Prepaid land use rights
Loans and Borrowings
Assets to secure long-term loans and borrowings	¥ 6,091	¥ 20,735

LOANS AND BORROWINGS - Aggregate maturities (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fiscal year ending December 31,
2018	¥ 327,538
2019	571,091
2020	839,502
2021	1,022,698
2022	715,457
Thereafter	311,017
Long-term borrowings	¥ 3,787,303	¥ 1,898,377

LOANS AND BORROWINGS - Particulars of secured long-term loans and borrowings (Details) ¥ in Thousands, $ in Thousands	1 Months Ended					12 Months Ended
	Dec. 31, 2017 CNY (¥)	Nov. 30, 2017 CNY (¥)	Oct. 31, 2017 USD ($)	Sep. 30, 2017 CNY (¥) subsidiary	Dec. 31, 2016 CNY (¥) subsidiary	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥) subsidiary	Dec. 31, 2009 CNY (¥)	Jun. 30, 2017 CNY (¥)	Mar. 31, 2017 USD ($) subsidiary	Sep. 30, 2016 CNY (¥) subsidiary	Dec. 31, 2014 CNY (¥)
Secured long-term loans and borrowings
Secured long-term loans and borrowings	¥ 3,620,053				¥ 1,898,377	¥ 3,620,053	¥ 1,898,377
Outstanding loans (net of debt issuance costs)	3,787,303				1,898,377	3,787,303	1,898,377
Debt issuance costs	134,395				74,246	134,395	74,246
Long-term loans guaranteed by William Wei Huang, Director and CEO of the Company	0				9,500	0	9,500
Accounts receivable
Secured long-term loans and borrowings
Assets pledged	136,043				87,347	136,043	87,347
Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	698,922				512,566	698,922	512,566
Prepaid land use rights
Secured long-term loans and borrowings
Assets pledged	6,091				20,735	6,091	20,735
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	161,000				189,179	¥ 161,000	¥ 189,179
Effective interest rate (as a percent)						4.90%	4.90%
Subsidiary A \| Entrusted credit facility with the local government \| Prepaid land use rights
Secured long-term loans and borrowings
Assets pledged	6,091				6,235	¥ 6,091	¥ 6,235
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
Effective interest rate (as a percent)							18.00%
Subsidiary B \| Credit facility with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged					13,367		¥ 13,367
Two Subsidiaries, A \| Loan facilities with third party banks
Secured long-term loans and borrowings
Principal amount of credit facility											¥ 1,135,000
Outstanding loans (net of debt issuance costs)	1,024,533				866,983	1,024,533	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%
Financial covenants, fails to repay any financial indebtedness in an aggregate amount											¥ 50,000
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 certain entities											99.90%
Two Subsidiaries, A \| Loan facilities with third party banks \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	35,185				8,185	35,185	8,185
Two Subsidiaries, A \| Loan facilities with third party banks \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	92,102				110,831	92,102	110,831
Two Subsidiaries, A \| Short term working capital loan
Secured long-term loans and borrowings
Outstanding loan amount	45,500				12,629	¥ 45,500	¥ 12,629
Effective interest rate (as a percent)						5.66%	5.66%
Two Subsidiaries, A \| Long term loans
Secured long-term loans and borrowings
Outstanding loans (net of debt issuance costs)	979,033				854,354	¥ 979,033	¥ 854,354
Two Subsidiaries, A \| Long term loans \| Minimum
Secured long-term loans and borrowings
Effective interest rate (as a percent)						7.05%	7.02%
Two Subsidiaries, A \| Long term loans \| Maximum
Secured long-term loans and borrowings
Effective interest rate (as a percent)						7.11%	7.34%
Subsidiary E \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Principal amount of credit facility											¥ 220,000
Outstanding loans (net of debt issuance costs)	196,708				137,334	¥ 196,708	¥ 137,334
Financial covenants, fails to repay any financial indebtedness in an aggregate amount											¥ 50,000
Subsidiary E \| Facility Agreement with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	25,368				30,110	25,368	30,110
Subsidiary E \| Facility Agreement with a third party bank \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	80,124				85,765	80,124	85,765
Subsidiary E \| Short term working capital loan
Secured long-term loans and borrowings
Outstanding loan amount	9,190				12,611	¥ 9,190	¥ 12,611
Effective interest rate (as a percent)						5.87%	5.87%
Subsidiary E \| Long term loans
Secured long-term loans and borrowings
Outstanding loans (net of debt issuance costs)	187,518				124,723	¥ 187,518	¥ 124,723
Effective interest rate (as a percent)						7.24%	7.63%
Subsidiary G \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Principal amount of credit facility					310,000		¥ 310,000
Outstanding loans (net of debt issuance costs)					106,510		106,510
Subsidiary G \| Facility Agreement with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged					2,466		2,466
Subsidiary G \| Facility Agreement with a third party bank \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged					138,941		138,941
Subsidiary G \| Facility Agreement with a third party bank \| Prepaid land use rights
Secured long-term loans and borrowings
Assets pledged					14,500		14,500
Subsidiary G \| 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 G \| 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%
Subsidiary H \| Secured long-term loans and borrowings
Secured long-term loans and borrowings
Outstanding loan amount					¥ 9,500		9,500
Effective interest rate (as a percent)					5.39%
Subsidiary H \| Secured long-term loans and borrowings \| Property and equipment, net \| William Wei Huang, Director and CEO of the Company
Secured long-term loans and borrowings
Assets pledged					¥ 23,376		23,376
Two Subsidiaries, B \| Loan facilities with third party banks
Secured long-term loans and borrowings
Principal amount of credit facility \| $										$ 45,000
Outstanding loans (net of debt issuance costs)	288,872					¥ 288,872
Effective interest rate (as a percent)						6.48%
Number of subsidiaries entered into loan facilities \| subsidiary										2
Early repayment if cease to own and control percentage of the equity interest in the borrowing subsidiaries										100.00%
Subsidiary I \| Project loan facility agreement with a third party bank
Secured long-term loans and borrowings
Principal amount of credit facility									¥ 644,000
Outstanding loans (net of debt issuance costs)	456,706					¥ 456,706
Early repayment if cease to own and control percentage of the equity interest in certain entities									100.00%
Financial covenants, fails to repay any financial indebtedness in an aggregate amount									¥ 50,000
Early repayment if STT GDC PTe. Ltd. ceases to own and control, directly or indirectly, the percentage of equity interest in the Company									25.00%
Early repayment if STT GDC PTe. Ltd. power to cast, or control the casting of voting in meeting, the percentage of equity interest in the Company									25.00%
Subsidiary I \| Project loan facility agreement with a third party bank \| GDS Beijing
Secured long-term loans and borrowings
Early repayment if cease to own and control percentage of the equity interest in the borrowing subsidiaries									100.00%
Subsidiary I \| Project loan facility agreement with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	14,831					14,831
Subsidiary I \| Project loan facility agreement with a third party bank \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	94,390					94,390
Subsidiary I \| Short term working capital loan
Secured long-term loans and borrowings
Outstanding loan amount	22,473					¥ 22,473
Effective interest rate (as a percent)						6.30%
Subsidiary I \| Long term loans
Secured long-term loans and borrowings
Outstanding loans (net of debt issuance costs)	434,233					¥ 434,233
Effective interest rate (as a percent)						6.82%
Two Subsidiaries, C \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Term of loan				5 years
Principal amount of credit facility				¥ 570,000
Outstanding loans (net of debt issuance costs)	511,017					¥ 511,017
Number of subsidiaries entered into loan facilities \| subsidiary				2
Early repayment if cease to own and control percentage of the equity interest in certain entities				100.00%
Financial covenants, fails to repay any financial indebtedness in an aggregate amount				¥ 50,000
Early repayment if STT GDC PTe. Ltd. ceases to own and control, directly or indirectly, the percentage of equity interest in the Company				25.00%
Early repayment if STT GDC PTe. Ltd. power to cast, or control the casting of voting in meeting, the percentage of equity interest in the Company				25.00%
Two Subsidiaries, C \| Facility Agreement with a third party bank \| GDS Management Company
Secured long-term loans and borrowings
Early repayment if cease to own and control percentage of the equity interest in certain entities				100.00%
Two Subsidiaries, C \| Facility Agreement with a third party bank \| GDS Beijing
Secured long-term loans and borrowings
Early repayment if cease to own and control percentage of the equity interest in certain entities				100.00%
Two Subsidiaries, C \| Facility Agreement with a third party bank \| Beijing Hengpu'an Data Technology Development Co., Ltd.
Secured long-term loans and borrowings
Early repayment if cease to own and control percentage of the equity interest in certain entities				100.00%
Two Subsidiaries, C \| Facility Agreement with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	17,649					17,649
Two Subsidiaries, C \| Facility Agreement with a third party bank \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	248,377					248,377
Two Subsidiaries, C \| Short term working capital loan
Secured long-term loans and borrowings
Outstanding loan amount	20,000					¥ 20,000
Two Subsidiaries, C \| Short term working capital loan \| Minimum
Secured long-term loans and borrowings
Effective interest rate (as a percent)						5.66%
Two Subsidiaries, C \| Short term working capital loan \| Maximum
Secured long-term loans and borrowings
Effective interest rate (as a percent)						6.30%
Two Subsidiaries, C \| Long term loans
Secured long-term loans and borrowings
Outstanding loans (net of debt issuance costs)	491,017					¥ 491,017
Two Subsidiaries, C \| Long term loans \| Minimum
Secured long-term loans and borrowings
Effective interest rate (as a percent)						6.26%
Two Subsidiaries, C \| Long term loans \| Maximum
Secured long-term loans and borrowings
Effective interest rate (as a percent)						7.13%
Two Subsidiaries , D \| 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
Number of subsidiaries entered into loan facilities \| subsidiary					2		2
Two Subsidiaries , D \| Loan facilities with third party banks \| Minimum
Secured long-term loans and borrowings
Effective interest rate (as a percent)							7.72%
Two Subsidiaries , D \| Loan facilities with third party banks \| Maximum
Secured long-term loans and borrowings
Effective interest rate (as a percent)							7.82%
Two Subsidiaries , D \| Loan facilities with third party banks \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged					¥ 13,305		¥ 13,305
Two Subsidiaries , D \| Loan facilities with third party banks \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged					¥ 153,653		¥ 153,653
Subsidiary J \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Term of loan			42 months
Principal amount of credit facility \| $			$ 25,000
Outstanding loans (net of debt issuance costs)	159,941					¥ 159,941
Effective interest rate (as a percent)						6.87%
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 cease to own and control percentage of the equity interest in the borrowing subsidiaries			100.00%
Financial covenants, fails to repay any financial indebtedness in an aggregate amount \| $			$ 4,500
Early repayment if STT GDC PTe. Ltd. ceases to own and control, directly or indirectly, the percentage of equity interest in the Company			25.00%
Early repayment if STT GDC PTe. Ltd. power to cast, or control the casting of voting in meeting, the percentage of equity interest in the Company			25.00%
Subsidiary J \| Facility Agreement with a third party bank \| 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 certain entities			99.90%
Subsidiary J \| Facility Agreement with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	3,015					¥ 3,015
Subsidiary K \| Short term working capital loan
Secured long-term loans and borrowings
Effective interest rate (as a percent)						5.66%
Subsidiary K \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Term of loan		5 years
Principal amount of credit facility		¥ 180,000
Outstanding loans (net of debt issuance costs)	169,984					¥ 169,984
Early repayment if cease to own and control percentage of the equity interest in certain entities		100.00%
Financial covenants, fails to repay any financial indebtedness in an aggregate amount		¥ 50,000
Early repayment if STT GDC PTe. Ltd. ceases to own and control, directly or indirectly, the percentage of equity interest in the Company		25.00%
Early repayment if STT GDC PTe. Ltd. power to cast, or control the casting of voting in meeting, the percentage of equity interest in the Company		25.00%
Subsidiary K \| Facility Agreement with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	27,003					27,003
Subsidiary K \| Facility Agreement with a third party bank \| Property and equipment, net
Secured long-term loans and borrowings
Assets pledged	183,929					183,929
Subsidiary K \| Short term working capital loan
Secured long-term loans and borrowings
Outstanding loan amount	15,782					15,782
Subsidiary K \| Long term loans
Secured long-term loans and borrowings
Outstanding loans (net of debt issuance costs)	154,202					¥ 154,202
Effective interest rate (as a percent)						6.92%
Subsidiary L \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Term of loan		6 years
Principal amount of credit facility		¥ 428,000
Outstanding loans (net of debt issuance costs)	¥ 402,057					¥ 402,057
Subsidiary L \| Long term loans
Secured long-term loans and borrowings
Effective interest rate (as a percent)						6.38%
Subsidiary M \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Term of loan	7 years
Principal amount of credit facility	¥ 1,010,000					¥ 1,010,000
Outstanding loans (net of debt issuance costs)	309,708					¥ 309,708
Effective interest rate (as a percent)						7.35%
Debt issuance costs	35,540					¥ 35,540
Subsidiary M \| Facility Agreement with a third party bank \| Accounts receivable
Secured long-term loans and borrowings
Assets pledged	¥ 1,377					1,377
Subsidiary N \| Loan facilities with third party banks
Secured long-term loans and borrowings
Term of loan		5 years
Principal amount of credit facility		¥ 200,000
Effective interest rate (as a percent)		9.70%
Subsidiary O \| Facility Agreement with a third party bank
Secured long-term loans and borrowings
Term of loan	10 years
Principal amount of credit facility	¥ 100,000					100,000
Outstanding loans (net of debt issuance costs)	¥ 52,472					¥ 52,472
Effective interest rate (as a percent)						6.69%

LOANS AND BORROWINGS - Particulars of unsecured long-term loans and borrowings (Details) - CNY (¥) ¥ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Oct. 31, 2017	Mar. 31, 2017
Unsecured long-term loans and borrowings
Outstanding loan amount	¥ 167,250	¥ 167,250
Subsidiary P \| Unsecured long-term loans and borrowings
Unsecured long-term loans and borrowings
Principal amount of credit facility				¥ 9,000
Outstanding loan amount	7,250	¥ 7,250
Effective interest rate (as a percent)		5.70%
Subsidiary Q \| Unsecured long-term loans and borrowings of facility agreements with third-party banks
Unsecured long-term loans and borrowings
Principal amount of credit facility	50,000	¥ 50,000
Outstanding loan amount	¥ 50,000	50,000
Effective interest rate (as a percent)	5.87%
Subsidiary R \| First unsecured long-term loans and borrowings of facility agreements with third-party banks
Unsecured long-term loans and borrowings
Principal amount of credit facility			¥ 100,000
Outstanding loan amount	¥ 100,000	¥ 100,000
Effective interest rate (as a percent)		5.23%
Subsidiary R \| Second unsecured long-term loans and borrowings of facility agreements with third-party banks
Unsecured long-term loans and borrowings
Principal amount of credit facility			¥ 10,000
Outstanding loan amount	¥ 10,000	¥ 10,000
Effective interest rate (as a percent)		7.00%

LOANS AND BORROWINGS - Total working capital and project financing credit (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Loans and Borrowings
Outstanding short-term borrowings	¥ 462,946	¥ 239,777
Outstanding loans (net of debt issuance costs)	3,787,303	1,898,377
Debt issuance costs	134,395	¥ 74,246
Credit Facilities
Loans and Borrowings
Total working capital and project financing credit facilities	5,371,555
Unused amount	986,911
Loan drew down	4,384,644
Debt issuance costs	134,395
Credit Facilities \| Short-term loans and borrowing
Loans and Borrowings
Outstanding short-term borrowings	462,946
Credit Facilities \| Long-term loans and borrowing
Loans and Borrowings
Outstanding loans (net of debt issuance costs)	¥ 3,787,303

CONVERTIBLE BONDS PAYABLE (Details) $ / shares in Units, ¥ in Thousands, $ in Thousands					1 Months Ended	12 Months Ended
	Jan. 29, 2016 USD ($)	Jan. 29, 2016 CNY (¥)	Dec. 30, 2015 USD ($) D tranche item $ / shares	Dec. 30, 2015 CNY (¥) D item	Nov. 30, 2017 CNY (¥) shares	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)	Nov. 30, 2017 $ / shares	Dec. 30, 2015 CNY (¥) tranche
CONVERTIBLE BONDS PAYABLE
Proceeds from convertible bonds							¥ 327,580	¥ 648,950
Gain or loss on change in fair value of derivative liability						¥ 0
Conversion of convertible securities							¥ 2,311,132
Convertible Bonds Due 2019
CONVERTIBLE BONDS PAYABLE
Number Of Investor \| item			2	2
Principal amount \| $			$ 250,000
Number of tranches \| tranche			4							4
Proceeds from convertible bonds	$ 50,000	¥ 324,475	$ 100,000	¥ 648,950
Unsubscribed bonds			$ 100,000							¥ 648,950
Interest per annum (as a percent)								5.00%
Maximum principal amount convertible to ordinary shares (as a percent)			100.00%							100.00%
Denominations for conversion of debt \| $			$ 10,000
Basis of issuance of shares for debt conversion (in dollar per share) \| $ / shares			$ 1.675262
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%
Percentage of principal amount of the original debt being converted									100.00%
shares issued value on conversion of convertible bonds					¥ 32
Conversion of convertible securities					¥ 1,106,195
Convertible Bonds Due 2019 \| Minimum
CONVERTIBLE BONDS PAYABLE
Trading days of stock price to trigger mandatory conversion \| D			10	10
Convertible Bonds Due 2019 \| Class A
CONVERTIBLE BONDS PAYABLE
Basis of issuance of shares for debt conversion (in dollar per share) \| $ / shares									$ 1.675262
Principal amount and accrued interest converted to Class A Ordinary shares (in shares) \| shares					97,870,263
Subsidiaries \| Convertible Bonds Due 2019
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, 2017	Dec. 31, 2016
ACCRUED EXPENSES AND OTHER PAYABLES
Accrued interest expenses	¥ 21,114	¥ 67,324
Accrued debt issuance costs	34,194
Income tax payable (note 20)	20,122	15,265
Consideration payables for acquisitions (note 8)	159,489	25,900
Other accrued expenses	101,275	71,924
Other payables	32,430	27,537
Total accrued expenses and other payables	¥ 368,624	¥ 207,950

LEASE - Capital lease and other financing obligations (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Capital lease obligations
Within 1 year	¥ 212,780	¥ 71,300
After 1 year but within 2 years	220,293	85,783
After 2 years but within 3 years	316,475	92,677
After 3 years but within 4 years	144,052	193,202
After 4 years but within 5 years	141,910	71,501
After 5 years	1,900,744	716,089
Total minimum lease payments	2,936,254	1,230,552
Less: total future interest	(1,209,120)	(552,060)
Present value of capital lease obligations	1,727,134	678,492
Other financing obligations
Within 1 year	45,007	22,044
After 1 year but within 2 years	63,151	38,443
After 2 years but within 3 years	75,685	39,548
After 3 years but within 4 years	76,678	41,586
After 4 years but within 5 years	80,832	42,287
After 5 years	1,469,318	725,178
Total other financing obligations	1,810,671	909,086
Less: total future interest	(905,590)	(450,670)
Less: estimated building costs	(231,228)	(25,356)
Present value of other financing obligations	673,853	433,060
Total
Within 1 year	257,787	93,344
After 1 year but within 2 years	283,444	124,226
After 2 years but within 3 years	392,160	132,225
After 3 years but within 4 years	220,730	234,788
After 4 years but within 5 years	222,742	113,788
After 5 years	3,370,062	1,441,267
Total	4,746,925	2,139,638
Less: total future interest	(2,114,710)	(1,002,730)
Less: estimated building costs	(231,228)	(25,356)
Present value of total obligations	2,400,987	1,111,552
Including:
Current Portion	97,943	88,593
Noncurrent portion	¥ 2,303,044	¥ 1,022,959
Weighted average effective interest rate of capital and built-to-suit leases (as a percent)	7.28%	8.04%

LEASE - Capital lease agreements (Details) - CNY (¥) ¥ in Thousands	1 Months Ended
	Nov. 30, 2017	Apr. 30, 2017	Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2016
Capital leases
Capital lease assets			¥ 2,539,520		¥ 1,248,303
Present value of minimum lease payments			¥ 1,727,134		¥ 678,492
Beijing 2 Lease
Capital leases
Capital lease assets				¥ 157,000
Capital lease obligations				157,000
Present value of minimum lease payments				¥ 157,000
Shanghai 5 and 8 Lease
Capital leases
Capital lease assets	¥ 262,206
Capital lease obligations	262,206
Present value of minimum lease payments	¥ 262,206
Shanghai 5 Lease
Capital leases
Term of capital lease		20 years 3 months
Shanghai 8 Lease
Capital leases
Term of capital lease	20 years
Hebei Equipment Lease
Capital leases
Term of capital lease	3 years
Capital lease assets	¥ 177,922
Capital lease obligations	177,922
Present value of minimum lease payments	¥ 177,922

LEASE - Build-to-suit leases (Details) - Shanghai 6 Lease And Shanghai 7 Lease, Build-to-suite ¥ in Thousands	1 Months Ended
	Oct. 31, 2017 CNY (¥) item
Build-to-suit leases
Number of buildings leased under build-to-suit lease \| item	2
Rent paid \| ¥	¥ 0
Percentage of total minimum lease payments due on termination of lease	50.00%
Term of capital lease	20 years

LEASE - Operating leases (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
LEASE - Operating leases (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Future minimum operating lease payments
2018	¥ 135,599
2019	101,152
2020	88,587
2021	48,939
2022	48,723
Thereafter	337,355
Total	760,355
Rental expenses	¥ 155,148	¥ 124,712	¥ 131,875

OTHER LONG-TERM LIABILITIES (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other long-term liabilities
Consideration payable for an acquisition	¥ 120,881
Payables for purchase of property and equipment	195,749	¥ 37,126
Accrued interests		51,112
Deferred government grants	16,789	14,051
Others	25,479	9,417
Total other long-term liabilities	¥ 358,898	¥ 111,706

REDEEMABLE PREFERRED SHARES - Movement (Details) - CNY (¥) ¥ in Thousands		1 Months Ended			4 Months Ended	12 Months Ended
	Aug. 13, 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
Change in redemption value						¥ 205,670	¥ (110,926)
Conversion to ordinary shares						2,311,132
Redeemable preferred shares
Movement of the redeemable preferred shares
Balance at beginning of year						¥ 2,395,314	¥ 2,164,039
Balance at beginning of year (in shares)						349,087,677	349,087,677
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
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
Balance at beginning of year (in shares)						29,635,045	29,635,045
Issuance of redeemable preferred shares - third party investor (in shares)				53,625,000
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(23,533,064)
Extinguishment of redeemable preferred shares upon exchange (in shares)					(10,081,891)
Change in redemption value						¥ (39,098)	¥ 4,029
Conversion to ordinary shares						¥ (72,965)
Conversion to ordinary shares (in shares)						(29,635,045)
Foreign exchange impact						¥ 4,635	6,125
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 (in shares)		14,149,705
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(5,503,899)
Extinguishment of redeemable preferred shares upon exchange (in shares)					(1,729,161)
Conversion to ordinary shares						¥ (43,564)
Conversion to ordinary shares (in shares)						(6,916,645)
Foreign exchange impact						¥ 3,989
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
Balance at beginning of year (in shares)						2,576,483	2,576,483
Issuance of redeemable preferred shares - third party investor (in shares)			11,550,000
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(8,413,412)
Extinguishment of redeemable preferred shares upon exchange (in shares)					(560,105)
Change in redemption value						¥ (3,921)	¥ 754
Conversion to ordinary shares						¥ (13,600)
Conversion to ordinary shares (in shares)						(2,576,483)
Foreign exchange impact						¥ 732	955
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 (in shares)		33,959,293
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(13,209,358)
Conversion to ordinary shares						¥ (88,221)
Conversion to ordinary shares (in shares)						(11,527,742)
Foreign exchange impact						¥ 8,073
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 (in shares)		25,618,413
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(9,964,954)
Conversion to ordinary shares						¥ (74,209)
Conversion to ordinary shares (in shares)						(10,435,639)
Foreign exchange impact						¥ 6,790
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 (in shares)		14,045,432
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(5,463,340)
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 (in shares)		23,037,763
Extinguishment of redeemable preferred shares upon repurchase (in shares)	(8,961,143)
Conversion to ordinary shares						¥ (96,287)
Conversion to ordinary shares (in shares)						(14,076,620)
Foreign exchange impact						¥ 8,810
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
Change in redemption value						¥ (21,016)	¥ 13,715
Conversion to ordinary shares						¥ (248,455)
Conversion to ordinary shares (in shares)						(35,393,262)
Foreign exchange impact						¥ 11,433	14,640
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 (in shares)	238,526,241
Change in redemption value						¥ (141,635)	¥ 92,428
Conversion to ordinary shares						¥ (1,673,831)
Conversion to ordinary shares (in shares)						(238,526,241)
Foreign exchange impact						¥ 77,026	98,629
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	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, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥) shares	Dec. 31, 2014 CNY (¥) shares
REDEEMABLE PREFERRED SHARES
Issuance of ordinary shares in exchange of bonds payable \| ¥										¥ 1,106,227
Change in redemption value \| ¥											¥ 205,670	¥ (110,926)
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
Carrying amount \| ¥												¥ 2,395,314	¥ 2,164,039
Change in redemption value \| ¥											(205,670)	¥ 110,926	¥ 69,116
Series A
REDEEMABLE PREFERRED SHARES
Shares outstanding												29,635,045	29,635,045
Carrying amount \| ¥												¥ 107,428	¥ 97,274
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
Change in redemption value \| ¥											(39,098)	¥ 4,029
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
Series B
REDEEMABLE PREFERRED SHARES
Shares outstanding												2,576,483	2,576,483
Carrying amount \| ¥												¥ 16,789	¥ 15,080
Shares issued				11,550,000	11,550,000
Issuance price per share \| (per share)				$ 0.7792	¥ 5.1087
Change in redemption value \| ¥											(3,921)	¥ 754
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
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
Series B3
REDEEMABLE PREFERRED SHARES
Shares issued in connection with acquisition			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
Series B5
REDEEMABLE PREFERRED SHARES
Shares outstanding												35,393,262	35,393,262
Carrying amount \| ¥												¥ 258,038	¥ 229,683
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
Change in redemption value \| ¥											(21,016)	¥ 13,715
Series C
REDEEMABLE PREFERRED SHARES
Shares outstanding												238,526,241	238,526,241
Carrying amount \| ¥												¥ 1,738,440	¥ 1,547,383
Shares issued	238,526,241	238,526,241
Issuance price per share \| (per share)	$ 1.0365	¥ 6.3779
Cash consideration for issuance of shares	$ 247,238	¥ 1,521,295
Issuance costs	$ 3,271	¥ 20,128
Change in redemption value \| ¥											¥ (141,635)	¥ 92,428

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	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 (¥)	Dec. 31, 2014 CNY (¥)	Dec. 22, 2014 CNY (¥)	Aug. 13, 2014 CNY (¥)
Redeemable preferred shares
REDEEMABLE PREFERRED SHARES
Carrying amount \| ¥									¥ 2,395,314	¥ 2,164,039
Shares exchanged							35,393,262	35,393,262
Series A
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	23,533,064	23,533,064
Carrying amount \| ¥									107,428	97,274
Shares exchanged							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
Carrying amount \| ¥									39,575	39,575
Shares exchanged							1,729,161	1,729,161
Series B
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	8,413,412	8,413,412
Carrying amount \| ¥									16,789	15,080
Shares exchanged							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
Carrying amount \| ¥									80,148	80,148
Series B2
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	9,964,954	9,964,954
Carrying amount \| ¥									67,419	67,419
Series B3
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	5,463,340	5,463,340
Series B4
REDEEMABLE PREFERRED SHARES
Number of shares repurchased	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
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
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) $ / shares in Units, $ in Thousands	Nov. 07, 2016 USD ($) $ / shares shares
Redeemable preferred shares
REDEEMABLE PREFERRED SHARES
Conversion ratio of preferred shares to ordinary share \| shares	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 \| shares	(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 \| shares	349,087,677

FAIR VALUE MEASUREMENT (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
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

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 shares	Oct. 18, 2016 Vote director	Aug. 13, 2014 USD ($) $ / shares shares	Aug. 13, 2014 CNY (¥) shares	Nov. 30, 2017 $ / shares shares	Oct. 31, 2017 $ / shares shares	Aug. 31, 2016 shares	Aug. 31, 2014 USD ($) shares	Aug. 31, 2014 CNY (¥) shares	Jun. 30, 2014 CNY (¥) shares	Dec. 31, 2017 CNY (¥) shares	Dec. 31, 2016 $ / shares shares	Dec. 31, 2006 $ / shares shares	Dec. 31, 2017 $ / shares shares	Dec. 30, 2015 $ / 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 \| ¥												¥ 1,106,227
Common stock, outstanding shares (in shares)													760,009,043		941,269,679
Ordinary shares issued as preferred stock dividends (in shares)		31,490,164
Convertible Bonds Due 2019
Ordinary shares
Percentage of principal amount of the original debt being converted						100.00%
Conversion price (in USD/share) \| $ / shares																$ 1.675262
Restricted shares
Ordinary shares
Granted (in shares)												13,977,060	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
Price per share (in USD/share) \| $ / shares		$ 1.25
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
Fair value of ordinary shares issued as part of the consideration to acquire EDC Holding \| ¥											¥ 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%
ADS
Ordinary shares
Price per share (in USD/share) \| $ / shares		$ 10.00
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)															873,679,343
Number of ADS per Class A ordinary share	8
Ordinary shares issued as preferred stock dividends (in shares)		31,490,164
Class A \| Convertible Bonds Due 2019
Ordinary shares
Conversion of convertible bonds (in shares)						97,870,263
Conversion price (in USD/share) \| $ / shares						$ 1.675262
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
CyrusOne Inc., \| Class A
Ordinary shares
Ordinary shares issued (in shares)							64,257,028
Price per share (in USD/share) \| $ / shares							$ 1.55625

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	Dec. 31, 2017 ¥ / shares shares	Dec. 31, 2016 ¥ / shares shares	Dec. 31, 2015 ¥ / shares shares	Aug. 31, 2016 shares	Jul. 31, 2014 shares
SHARE-BASED COMPENSATION
Share options granted (in shares)					333,334	11,551,507	519,271
Exercise price (in USD or CNY per share) \| ¥ / shares					¥ 5.2	¥ 5.2	¥ 4.8
External consultants
SHARE-BASED COMPENSATION
Unvested options (in shares)					266,666	600,000
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)					0	333,334
Installment period in each installment			6 months	6 months
Number of installments \| installment			6	6
Employees, officers and directors \| Share options
SHARE-BASED COMPENSATION
Share options granted (in shares)	11,084,840	11,084,840
Exercise price (in USD or CNY per share) \| (per share)	$ 0.7792	¥ 5.0328
Contractual term	5 years	5 years
The 2014 Plan
SHARE-BASED COMPENSATION
Total number shares which may be issued									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, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of options
Outstanding, beginning (in shares)	28,589,782	17,193,534	17,463,207
Granted (in shares)	333,334	11,551,507	519,271
Exercised (in shares)	(816,880)
Forfeited (in shares)	(19,000)	(155,259)	(788,944)
Outstanding, ending (in shares)	28,087,236	28,589,782	17,193,534
Weighted average exercise price
Outstanding, beginning (in RNB per share)	¥ 5.2	¥ 4.8
Granted (in RMB per share)	5.2	5.2	¥ 4.8
Exercised (in RMB per share)	5.3
Forfeited (in RMB per share)	5.3	4.8	4.8
Outstanding, ending (in RMB per share)	5.1	5.2	4.8
Weighted average grant-date fair value per option
Outstanding, beginning (in RMB per share)	3.2	1.9
Granted (in RMB per share)	10.6	4.9	1.9
Exercised (in RMB per share)	1.9
Forfeited (in RMB per share)	1.9	1.9	1.9
Outstanding, ending (in RMB per share)	¥ 3.2	¥ 3.2	¥ 1.9
Options vested and expect to vest
Number of options	28,087,236
Weighted average exercise price (in RMB per share)	¥ 5.1
Weighted average grant-date fair value per option (in RMB per share)	¥ 3.2
Stock options outstanding and stock options exercisable
Number of shares	28,087,236
Weighted average remaining contractual life (years)	2 years 2 months 12 days
Weighted average exercise price (in RMB per share)	¥ 5.1
External consultants
Other disclosures
Forfeitable and unvested (in shares)	266,666	600,000
Employee stock options
Other disclosures
Forfeitable and unvested (in shares)	0	0

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

SHARE-BASED COMPENSATION - Settlement of Liability Classified Restricted Shares (Details) - CNY (¥) ¥ in Thousands	1 Months Ended		7 Months Ended	12 Months Ended
	Aug. 31, 2016	May 31, 2016	Nov. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
SHARE-BASED COMPENSATION
Compensation expense				¥ 59,843	¥ 64,165	¥ 4,061
Settlement of liability-classified restricted shares award				4,462	7,539
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		0
Liability paid in cash	¥ 4,194
Restricted shares
SHARE-BASED COMPENSATION
Compensation expense				¥ 56,237	¥ 4,697
Restricted shares \| Directors
SHARE-BASED COMPENSATION
Settlement of liability-classified restricted shares award			¥ 4,462
Settlement of liability-classified restricted shares award (in shares)	877,400		502,000
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
	Jul. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Weighted average grant-date fair value per share (RMB)
Total share based compensation expense			¥ 59,843	¥ 64,165	¥ 4,061
Restricted shares
Number of Shares
Outstanding, beginning			12,910,080
Granted (in shares)			13,977,060	13,787,480
Vested (in shares)			(2,123,120)	(877,400)
Forfeited (in shares)			(238,400)
Outstanding, end		12,910,080	24,525,620	12,910,080
Weighted average grant-date fair value per share (RMB)
Outstanding, beginning			¥ 6.0
Granted (in RMB per share)			5.2	¥ 6.1
Vested (in RMB per share)			8.5	8.6
Forfeited (in RMB per share)			6.8
Outstanding, end		¥ 6.0	¥ 5.3	¥ 6.0
Total share based compensation expense			¥ 56,237	¥ 4,697
Total unrecognized compensation expense			¥ 81,306
Weighted average period over which unrecognized compensation expense is expected to be recognized			1 year 10 months 17 days
Restricted shares \| Employees, officers and directors
Number of Shares
Granted (in shares)	13,475,060	12,910,080

SHARE-BASED COMPENSATION - Fair Value Assumptions - Restricted Shares (Details) - Restricted shares	7 Months Ended	12 Months Ended
	Jul. 31, 2017 $ / shares	Dec. 31, 2016 $ / shares	Jul. 31, 2017 ¥ / shares	Dec. 31, 2016 ¥ / shares
Fair value assumptions
Share price at grant date \| (per share)	$ 1.191	$ 1.24	¥ 8.00	¥ 8.60
Maximum
Fair value assumptions
Risk-free rate of return (as a percent)	1.63%	1.65%
Volatility (as a percent)	21.48%	24.80%
Expected term	4 years	5 years
Minimum
Fair value assumptions
Risk-free rate of return (as a percent)	1.29%	0.68%
Volatility (as a percent)	20.43%	22.35%
Expected term	2 years	1 year

SHARE-BASED COMPENSATION - Expenses (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
SHARE-BASED COMPENSATION
Compensation expense	¥ 59,843	¥ 64,165	¥ 4,061
Cost of revenue
SHARE-BASED COMPENSATION
Compensation expense	9,941	2,114	484
Selling and marketing expenses
SHARE-BASED COMPENSATION
Compensation expense	18,390	6,590	325
General and administrative expenses
SHARE-BASED COMPENSATION
Compensation expense	30,866	55,409	¥ 3,252
Research and development expenses
SHARE-BASED COMPENSATION
Compensation expense	¥ 646	¥ 52

REVENUE (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
REVENUE (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net revenue
Service revenue	¥ 1,591,860	¥ 1,003,015	¥ 653,591
Equipment sales	24,306	52,945	50,045
Net revenue	¥ 1,616,166	¥ 1,055,960	¥ 703,636

INCOME TAX - Tax rate (Details)	12 Months Ended
INCOME TAX - Tax rate (Details)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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, 2017	Dec. 31, 2016	Dec. 31, 2015
Loss before income taxes:
PRC	¥ 130,961	¥ 144,158	¥ 94,190
Other jurisdictions	202,015	140,569	16,377
Total loss before income taxes	332,976	284,727	110,567
Current tax expenses:
PRC	5,546	311	(1,650)
Other jurisdictions		1,998	256
Total current tax (benefits) expenses	5,546	2,309	(1,394)
Deferred tax benefits:
PRC	(11,683)	(10,935)	(10,589)
Other jurisdictions	61	311
Total deferred tax benefits	(11,622)	(10,624)	(10,589)
Total income taxes benefits	¥ (6,076)	¥ (8,315)	¥ (11,983)

INCOME TAX - Reconciliation of statutory tax rate and effective tax rate (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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)	(14.80%)	(13.70%)	(3.80%)
Tax differential for entities in non-PRC jurisdiction (as a percent)	(0.80%)	0.50%	0.00%
Tax effect of permanent differences (as a percent)	0.00%	(0.30%)	(0.60%)
Change in valuation allowance (as a percent)	(7.80%)	(8.40%)	(9.40%)
Return to provision adjustment	0.20%	(0.20%)	(0.40%)
Effective tax rate (as a percent)	1.80%	2.90%	10.80%

INCOME TAX - Deferred tax assets and liabilities (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Government subsidy	¥ 4,197	¥ 3,763
Accrued expenses	14,024	23,324
Asset retirement obligation	4,412	2,377
Net operating loss carry forwards	170,267	141,749
Total gross deferred tax assets	192,900	171,213
Valuation allowance on deferred tax assets	(152,241)	(134,935)	¥ (118,952)	¥ (116,403)
Deferred tax assets, net of valuation allowance	40,659	36,278
Deferred tax liabilities:
Property and equipment	(52,417)	(36,644)
Intangible assets	(82,305)	(22,914)
Prepaid land use rights	(1,693)	(1,733)
Obligation under capital lease and other financing obligations	(14,216)	(15,641)
Total deferred tax liabilities	(150,631)	(76,932)
Net deferred tax liabilities	(109,972)	(40,654)
Analysis as:
Deferred tax assets	14,305	12,626
Deferred tax liabilities	(124,277)	(53,280)
Net deferred tax liabilities	¥ (109,972)	¥ (40,654)

INCOME TAX - Movement of the valuation allowance (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Movement of the valuation allowance
Balance at the beginning of the year	¥ 134,935	¥ 118,952	¥ 116,403
Increase during the year	17,306	15,983	2,549
Balance at the end of the year	¥ 152,241	¥ 134,935	¥ 118,952

INCOME TAX - Net operating losses (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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	¥ 652,043
Net operating losses carry forwards expire if unused by December 31, 2018	193,880
Net operating losses carry forwards expire if unused by December 31, 2019	60,137
Net operating losses carry forwards expire if unused by December 31, 2020	113,187
Net operating losses carry forwards expire if unused by December 31, 2021	76,752
Net operating losses carry forwards expire if unused by December 31, 2022	¥ 208,087
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, 2017	Dec. 31, 2016
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	¥ 2,495,075	¥ 1,975,175
Amount of non-distributable general reserve fund	¥ 214	¥ 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, 2017 CNY (¥) ¥ / shares shares	Dec. 31, 2016 CNY (¥) ¥ / shares shares	Dec. 31, 2015 CNY (¥) ¥ / shares shares
Computation of basic and diluted loss per share
Net loss			¥ 326,900	¥ 276,412	¥ 98,584
Change in redemption value of redeemable preferred shares				(205,670)	110,926
(Cumulative) Dividend on preferred shares				332,660	7,127
Net loss attributable to ordinary shareholders			¥ 326,900	¥ 403,402	¥ 216,637
Weighted average number of ordinary shares outstanding-basic and diluted \| shares			784,566,371	299,093,937	217,987,922
Loss per ordinary share - basic and diluted \| ¥ / shares			¥ (0.42)	¥ (1.35)	¥ (0.99)
Conversion of preferred shares to ordinary shares				¥ 97,274
Dividends on redeemable preferred shares				302,944
Preference dividends	$ 50,812	¥ 343,296		¥ 343,296
Ordinary Shares
Computation of basic and diluted loss per share
Shares issued to depository bank (in shares) \| shares			20,000,000
Consideration received on issuance of ordinary share to its share depository bank			¥ 0

LOSS PER ORDINARY SHARE - Excluded from the computation of diluted loss per share (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive securities excluded from computation of earnings per share
Total	52,612,856	135,477,699	425,973,367
Share options/restricted shares
Antidilutive securities excluded from computation of earnings per share
Total	52,612,856	41,499,862	17,193,534
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

SEGMENT INFORMATION (Details)	12 Months Ended
SEGMENT INFORMATION (Details)	Dec. 31, 2017 segment
SEGMENT INFORMATION
Number of operating segments	1

MAJOR CUSTOMERS (Details) ¥ in Thousands	12 Months Ended
MAJOR CUSTOMERS (Details) ¥ in Thousands	Dec. 31, 2017 CNY (¥) customer	Dec. 31, 2016 CNY (¥) customer	Dec. 31, 2015 CNY (¥) customer
MAJOR CUSTOMERS
Revenue	¥ 1,616,166	¥ 1,055,960	¥ 703,636
Revenues \| Customer concentration
MAJOR CUSTOMERS
Number of customers generated over 10% of the Company's total revenues \| customer	3	2	1
Revenues \| Customer concentration \| Customer A
MAJOR CUSTOMERS
Revenue	¥ 318,359	¥ 169,052	¥ 141,711
Revenues \| Customer concentration \| Customer B
MAJOR CUSTOMERS
Revenue	166,384	¥ 153,863
Revenues \| Customer concentration \| Customer C
MAJOR CUSTOMERS
Revenue	¥ 163,719

COMMITMENTS - Capital commitments (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016
COMMITMENTS
Capital commitments outstanding not provided for in the financial statements, Contracted for	¥ 1,065,551	¥ 510,999

RELATED PARTY TRANSACTIONS (Details) $ / shares in Units, ¥ in Thousands, $ in Thousands					1 Months Ended	12 Months Ended
	Nov. 07, 2016 USD ($) $ / shares shares	Nov. 07, 2016 CNY (¥) shares	Jan. 29, 2016 USD ($)	Jan. 29, 2016 CNY (¥)	Nov. 30, 2017 CNY (¥) shares	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 CNY (¥)	Nov. 30, 2017 $ / shares	Jan. 29, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)
RELATED PARTY TRANSACTIONS
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
Conversion of convertible bonds from a related party						¥ 366,958
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
Outstanding short-term loan repaid by a loan from related party							65,474
Outstanding short-term borrowings						462,946	239,777
Affiliated Entity
RELATED PARTY TRANSACTIONS
Preference dividends							343,296
STT GDC Pte. Ltd.
RELATED PARTY TRANSACTIONS
Preference dividends							223,225
Interest expenses						¥ 30,078	32,245	$ 397	¥ 2,579
Short-term loan								$ 10,000				¥ 64,936
Convertible bonds 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
Accrued but unpaid cash interest relinquished					¥ 4,991
SBCVC
RELATED PARTY TRANSACTIONS
Preference dividends							109,665
Other non-principal preferred shareholders
RELATED PARTY TRANSACTIONS
Preference dividends							¥ 10,406
ADS
RELATED PARTY TRANSACTIONS
Initial public offering price (dollar per share) \| $ / shares	$ 10.00
Class A
RELATED PARTY TRANSACTIONS
Ordinary shares issued as preferred stock dividends (in shares) \| shares	31,490,164	31,490,164
Class A \| STT GDC Pte. Ltd.
RELATED PARTY TRANSACTIONS
Principal amount and accrued interest converted to Class A Ordinary shares (in shares) \| shares					32,540,515
Basis of issuance of shares for debt conversion (in dollar per share) \| $ / shares										$ 1.675262
Ordinary Shares
RELATED PARTY TRANSACTIONS
Initial public offering price (dollar per share) \| $ / shares	$ 1.25

PARENT ONLY FINANCIAL INFORMATION - Condensed Balance Sheets (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current assets
Cash	¥ 1,873,446	¥ 1,811,319
Prepaid expenses	50,373	50,361
Total current assets	2,454,028	2,210,313
Other non-current assets	211,785	98,725
Total assets	13,144,567	8,203,866
Current liabilities
Accounts payable	1,110,411	513,543
Accrued expenses and other payables	368,624	207,950
Total current liabilities	2,423,071	1,479,221
Convertible bonds payable		1,040,550
Other long-term liabilities	358,898	111,706
Total liabilities	8,669,055	5,217,392
Shareholders' Equity
Ordinary shares (US$0.00005 par value; 2,002,000,000 shares authorized; 760,009,043 and 941,269,679 shares issued and outstanding as of December 31, 2016 and 2017, respectively)	320	260
Additional paid-in capital	5,861,445	4,036,959
Accumulated other comprehensive loss	(200,688)	(192,080)
Accumulated deficit	(1,185,565)	(858,665)
Total shareholders' equity	4,475,512	2,986,474	¥ (340,505)	¥ (16,565)
Commitments and contingencies
Total liabilities and shareholders' equity	13,144,567	8,203,866
Parent Company
Current assets
Cash	999,194	1,030,627
Prepaid expenses	6,295	1,011
Total current assets	1,005,489	1,031,638
Investment and loans to subsidiaries	3,477,331	3,054,835
Other non-current assets	14,936	15,856
Total assets	4,497,756	4,102,329
Current liabilities
Accounts payable	3,597
Accrued expenses and other payables	9,973	23,266
Due to subsidiaries	843	927
Total current liabilities	14,413	24,193
Convertible bonds payable		1,040,550
Other long-term liabilities	7,831	51,112
Total liabilities	22,244	1,115,855
Shareholders' Equity
Ordinary shares (US$0.00005 par value; 2,002,000,000 shares authorized; 760,009,043 and 941,269,679 shares issued and outstanding as of December 31, 2016 and 2017, respectively)	320	260
Additional paid-in capital	5,861,445	4,036,959
Accumulated other comprehensive loss	(200,688)	(192,080)
Accumulated deficit	(1,185,565)	(858,665)
Total shareholders' equity	4,475,512	2,986,474
Commitments and contingencies
Total liabilities and shareholders' equity	¥ 4,497,756	¥ 4,102,329

PARENT ONLY FINANCIAL INFORMATION - Condensed Balance Sheets (Parenthetical) (Details) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Condensed Balance Sheets
Ordinary shares, par value (in dollars per share)	$ 0.00005	$ 0.00005
Ordinary shares, shares authorized	2,002,000,000	2,002,000,000
Ordinary shares, shares issued	941,269,679	760,009,043
Ordinary shares, shares outstanding	941,269,679	760,009,043
Parent Company
Condensed Balance Sheets
Ordinary shares, par value (in dollars per share)	$ 0.00005	$ 0.00005
Ordinary shares, shares authorized	2,002,000,000	2,002,000,000
Ordinary shares, shares issued	941,269,679	760,009,043
Ordinary shares, shares outstanding	941,269,679	760,009,043

PARENT ONLY FINANCIAL INFORMATION - Condensed Statements of Operations (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Statements of Operations
Net revenue	¥ 1,616,166	¥ 1,055,960	¥ 703,636
Cost of revenue	(1,207,694)	(790,286)	(514,997)
Gross loss	408,472	265,674	188,639
Operating expenses
Selling and marketing expenses	(90,118)	(71,578)	(57,588)
General and administrative expenses	(228,864)	(227,370)	(128,714)
Research and development expenses	(7,261)	(9,100)	(3,554)
(Loss) Income from operations	82,229	(42,374)	(1,217)
Other income (expenses):
Interest income	5,600	2,070	1,355
Interest expenses	(412,003)	(265,234)	(126,901)
Others, net	435	284	1,174
Loss before income taxes	(332,976)	(284,727)	(110,567)
Income tax expenses	6,076	8,315	11,983
Net loss	(326,900)	(276,412)	(98,584)
Parent Company
Condensed Statements of Operations
Cost of revenue	(10,392)	(2,381)
Gross loss	(10,392)	(2,381)
Operating expenses
Selling and marketing expenses	(22,528)	(8,914)	(1,566)
General and administrative expenses	(59,500)	(82,794)	(14,665)
Research and development expenses	(646)	(52)
(Loss) Income from operations	(93,066)	(94,141)	(16,231)
Other income (expenses):
Interest income	3,901	16
Interest expenses	(90,408)	(97,603)	(3,297)
Equity in loss of subsidiaries	(147,340)	(84,952)	(79,056)
Others, net	13	268
Loss before income taxes	(326,900)	(276,412)	(98,584)
Net loss	¥ (326,900)	¥ (276,412)	¥ (98,584)

PARENT ONLY FINANCIAL INFORMATION - Condensed Statements of Comprehensive Loss (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Statements of Comprehensive Loss
Net loss	¥ (326,900)	¥ (276,412)	¥ (98,584)
Other comprehensive loss
Foreign currency translation adjustments, net of nil tax	(8,608)	(130,131)	(118,491)
Comprehensive loss	(335,508)	(406,543)	(217,075)
Parent Company
Condensed Statements of Comprehensive Loss
Net loss	(326,900)	(276,412)	(98,584)
Other comprehensive loss
Foreign currency translation adjustments, net of nil tax	(8,608)	(130,131)	(118,491)
Comprehensive loss	¥ (335,508)	¥ (406,543)	¥ (217,075)

PARENT ONLY FINANCIAL INFORMATION - Condensed Statements of Comprehensive Loss (Parenthetical) (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)
Operating activities:
Net cash used in operating activities			¥ (174,612)	¥ (150,228)	¥ (80,298)
Investing activities:
Deposit paid for potential acquisitions			(5,000)	(15,000)
Net cash used in investing activities			(2,035,778)	(1,147,064)	(731,905)
Financing activities:
Proceeds from exercise of stock options			3,377
Proceeds from issuance of convertible bonds				327,580	648,950
Repayment of bonds payable					(14,330)
Proceeds from a related party loan					64,936
Repayment of a related party loan				(65,474)
Net proceeds from issuance of ordinary shares			649,834	1,221,518
Payment of preferred shares dividends				(76,502)
Repurchase of redeemable preferred shares					(23,300)
Net cash provided by financing activities			2,346,767	2,128,614	1,127,685
Effect of exchange rate changes on cash			(74,250)	55,499	2,258
Net increase in cash			62,127	886,821	317,740
Cash at beginning of year			1,811,319	924,498	606,758
Cash at end of year			1,873,446	1,811,319	924,498
Supplemental disclosures of cash flow information
Interest paid			358,748	228,678	81,216
Supplemental disclosures of non-cash investing and financing activities
Issuance of ordinary shares to settle preference dividend	$ 39,363	¥ 266,794		266,794
Conversion of convertible bonds			1,106,227
Parent Company
Operating activities:
Net cash used in operating activities			(58,068)	(62,591)	(4,895)
Investing activities:
Deposit paid for potential acquisitions				(15,000)
Increase of due from subsidiaries			(588,768)	(990,617)	(93,101)
Net cash used in investing activities			(588,768)	(1,005,617)	(93,101)
Financing activities:
Proceeds from exercise of stock options			3,377
Proceeds from issuance of convertible bonds				327,580	648,950
Repayment of bonds payable					(14,330)
Proceeds from a related party loan					64,936
Repayment of a related party loan				(65,474)
Net proceeds from issuance of ordinary shares			649,834	1,221,518
Payment of preferred shares dividends				(76,502)
Repurchase of redeemable preferred shares					(23,300)
Net cash provided by financing activities			653,211	1,407,122	676,256
Effect of exchange rate changes on cash			(37,808)	47,787	57,565
Net increase in cash			(31,433)	386,701	635,825
Cash at beginning of year			1,030,627	643,926	8,101
Cash at end of year			999,194	1,030,627	643,926
Supplemental disclosures of cash flow information
Interest paid			33,920	45,495	¥ 3,463
Supplemental disclosures of non-cash investing and financing activities
Issuance of ordinary shares to settle preference dividend				¥ 266,794
Conversion of convertible bonds			¥ 1,106,227

SUBSEQUENT EVENTS (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 29, 2018	Jan. 26, 2018	Dec. 06, 2016
Subsequent Event
SUBSEQUENT EVENTS
Gross proceeds from issue of stock before deducting underwriting discounts and commissions	$ 213,850
ADS \| Over-Allotment Option
SUBSEQUENT EVENTS
Ordinary shares issued (in shares)			820,735
ADS \| Subsequent Event
SUBSEQUENT EVENTS
Ordinary shares issued (in shares)		8,000,000
Price per share sold (in dollars per ADS)		$ 26.00
ADS \| Subsequent Event \| SBCVC
SUBSEQUENT EVENTS
Number of shares sold		3,000,000
Price per share sold (in dollars per ADS)		$ 26.00
ADS \| Subsequent Event \| Over-Allotment Option
SUBSEQUENT EVENTS
Ordinary shares issued (in shares)	225,000
ADS \| Subsequent Event \| SBCVC \| Over-Allotment Option
SUBSEQUENT EVENTS
Ordinary shares issued (in shares)	1,425,000
Class A \| Over-Allotment Option
SUBSEQUENT EVENTS
Ordinary shares issued (in shares)			6,565,880
Class A \| Subsequent Event
SUBSEQUENT EVENTS
Ordinary shares issued (in shares)		64,000,000
Class A \| Subsequent Event \| SBCVC
SUBSEQUENT EVENTS
Number of shares sold		24,000,000
Class A \| Subsequent Event \| Over-Allotment Option
SUBSEQUENT EVENTS
Ordinary shares issued (in shares)	1,800,000
Class A \| Subsequent Event \| SBCVC \| Over-Allotment Option
SUBSEQUENT EVENTS
Ordinary shares issued (in shares)	11,400,000