SECURITIES AND EXCHANGE COMMISSION 

Washington, D.C. 20549

FORM 6-K

Report of Foreign Private Issuer

Pursuant toRule 13a-16 or 15d-16 of

the Securities Exchange Act of 1934

August 2025

Commission File Number: 001-37925

GDS Holdings Limited 

(Registrant’s name)

F4/F5, Building C, Sunland International

No. 999 Zhouhai Road 

Pudong, Shanghai 200137

People’s Republic of China 

(Address of principal executive offices)

Indicate by check mark whether the registrant files or willfile annual reports under cover of Form 20-F or Form 40-F:

Form 20-Fx Form 40-F ¨

EXHIBITS

SIGNATURES

Pursuant to the requirements of theSecurities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto dulyauthorized.

Exhibit 99.1

GDS Reports

Second Quarter 2025 Results

GDS Holdings Limited Reports Second Quarter2025 Results

Shanghai, China,August 20, 2025 – GDS Holdings Limited (“GDS Holdings”, “GDS” or the “Company”)(NASDAQ: GDS; HKEX: 9698), a leading developer and operator of high-performance data centers in China, today announced its unaudited financialresults for the second quarter ended June 30, 2025.

Second Quarter 2025 Financial Highlights

Second Quarter 2025 Operating Highlights

“Our disciplined execution drove anotherquarter of solid operational and financial performance,” stated Mr. William Huang, Chairman and CEO of GDS. “We continuedto accelerate the delivery of our backlog while maintaining a selective approach to new orders. The successful initial public offeringof our C-REIT on the Shanghai Stock Exchange marks a key strategic milestone. Moving forward to the second half of the year, we are well-positionedto capture new business opportunities in Tier 1 markets, driven by tailwinds of AI evolution.”

“In the second quarter of 2025, our revenueincreased by 12.4% and adjusted EBITDA grew by 11.2% year-over-year, with an adjusted EBITDA margin of 47.3%. On the funding side, weraised net proceeds of US$676 million through new convertible senior notes and equity. Our new C-REIT platform provides us with enhancedfinancing flexibility. We remain focused on creating sustainable, long-term value for our business partners and shareholders,” Mr. DanNewman, Chief Financial Officer, added.

Second Quarter 2025 Financial Results For Continuing Operations

Net revenue in thesecond quarter of 2025 was RMB2,900.3 million (US$404.9 million), a 12.4% increase over the same period last year of RMB2,579.6million. The Y-o-Y increase was mainly due to continued ramp-up of our data centers.

Cost of revenuein the second quarter of 2025 was RMB2,211.4 million (US$308.7 million), a 9.8% increase over the same period last year of RMB2,013.9million. The Y-o-Y increase was in line with the continued ramp-up of our data centers.

Gross profit wasRMB688.9 million (US$96.2 million) in the second quarter of 2025, a 21.8% increase over the same period last year of RMB565.7 million.

Gross profit marginwas 23.8% in the second quarter of 2025, compared with 21.9% in the same period last year. The Y-o-Y increase was mainly due toa lower level of operating costs as a percentage of net revenue as our data centers continue to ramp up.

Adjusted Gross Profit(“Adjusted GP”) (non-GAAP) is defined as gross profit excluding depreciation and amortization, operating lease cost relatingto prepaid land use rights, accretion expenses for asset retirement costs and share-based compensation expenses allocated to cost of revenue.Adjusted GP was RMB1,509.5 million (US$210.7 million) in the second quarter of 2025, a 14.0% increase over the same period lastyear of RMB1,324.3 million. See “Non-GAAP Disclosure” and “Reconciliations of GAAP and non-GAAP results” elsewherein this earnings release.

Adjusted GP margin(non-GAAP) was 52.0% in the second quarter of 2025, compared with 51.3% in the same period last year. The Y-o-Y increase was mainlydue to a lower level of cash operating costs as a percentage of net revenue as our data centers continue to ramp up.

Selling and marketingexpenses, excluding share-based compensation expenses of RMB5.5 million (US$0.8 million), were RMB28.5 million (US$4.0 million) in thesecond quarter of 2025, a 47.9% increase over the same period last year of RMB19.3 million (excluding share-based compensationof RMB4.0 million). The Y-o-Y increase was mainly due to higher sales-related personnel costs.

General and administrativeexpenses, excluding share-based compensation expenses of RMB40.4 million (US$5.6 million), depreciation and amortization expenses of RMB62.6million (US$8.7 million) and operating lease cost relating to prepaid land use rights of RMB15.6 million (US$2.2 million), were RMB113.0million (US$15.8 million) in the second quarter of 2025, a 46.6% increase over the same period last year of RMB77.1 million (excludingshare-based compensation expenses of RMB39.7 million, depreciation and amortization expenses of RMB71.2 million and operating lease costrelating to prepaid land use rights of RMB16.9 million). The Y-o-Y increase was mainly due to an increase in corporate expenses in linewith business growth.

Research and developmentcosts were RMB8.8 million (US$1.2 million) in the second quarter of 2025, compared with RMB10.9 million in the same period lastyear.

Net interest expensesfor the second quarter of 2025 were RMB405.0 million (US$56.5 million), a 10.1% decrease over the same period last year of RMB450.3million. The Y-o-Y decrease was mainly due to a lower level of total borrowings, lower interest rates and higher interest income earnedon cash proceeds from our recent capital market transactions which was put on deposit.

Foreign currencyexchange gain for the second quarter of 2025 was RMB1.4 million (US$0.2 million), compared with RMB3.4 million in the same periodlast year.

Others, net forthe second quarter of 2025 was positive RMB9.2 million (US$1.3 million), compared with positive RMB7.2 million in the same periodlast year.

Income tax expenses for the second quarter of2025 were RMB64.9 million (US$9.1 million), compared with RMB59.9 million in the same period last year.

Share of results of equity method investees forthe second quarter of 2025 was a loss of RMB25.9 million (US$3.6 million), mainly arising from our investment in DayOne Data Centers Limited,compared with nil in the same period last year.

Net loss in thesecond quarter of 2025 was RMB70.6 million (US$9.9 million), compared with RMB231.8 million in the same period last year. The Y-o-Ydecrease was mainly due to the faster ramp-up of our data centers.

Basic loss per ordinaryshare in the second quarter of 2025 was RMB0.06 (US$0.01), compared with RMB0.16 in the same period last year. Diluted loss perordinary share in the second quarter of 2025 was RMB0.06 (US$0.01), compared with RMB0.16 in the same period last year.

Basic loss per AmericanDepositary Share (“ADS”) in the second quarter of 2025 was RMB0.46 (US$0.06), compared with RMB1.30 in the same periodlast year. Diluted loss per ADS in the second quarter of 2025 was RMB0.46 (US$0.06), compared with RMB1.30 in the same period last year.

Adjusted EBITDA(non-GAAP) is defined as net income (loss) excluding income (loss) from discontinued operations, net interest expenses, income tax expenses(benefits), depreciation and amortization, operating lease cost relating to prepaid land use rights, accretion expenses for assetretirement costs, share-based compensation expenses, gain from purchase price adjustment, impairment losses of long-lived assets, shareof results of equity method investees and gain on deconsolidation of subsidiaries. Adjusted EBITDA was RMB1,371.8 million (US$191.5 million)in the second quarter of 2025, an 11.2% increase over the same period last year of RMB1,233.2 million.

Adjusted EBITDAmargin (non-GAAP) was 47.3% in the second quarter of 2025, compared with 47.8% in the same period last year. The Y-o-Y decreasewas mainly due to an increase in corporate expenses as a percentage of net revenue.

Liquidity

As of June 30, 2025, cash was RMB13,123.8million (US$1,832.0 million).

Total short-term debt was RMB4,493.1 million (US$627.2million), comprised of short-term borrowings and the current portion of long-term borrowings of RMB3,819.8 million (US$533.2 million)and the current portion of finance lease and other financing obligations of RMB673.3 million (US$94.0 million). Total long-term debt wasRMB41,942.2 million (US$5,854.9 million), comprised of long-term borrowings (excluding current portion) of RMB22,321.2 million (US$3,115.9million), the non-current portion of convertible bonds payable of RMB12,344.7 million (US$1,723.3 million) and the non-current portionof finance lease and other financing obligations of RMB7,276.3 million (US$1,015.7 million).

During the secondquarter of 2025, the Company obtained new debt financing and refinancing facilities of RMB4,451.0 million (US$621.3 million). Duringthe second quarter of 2025, the Company also raised net cash proceeds of approximately US$534.9 million through the issuance of new convertiblesenior notes and US$141.6 million through the issuance of new equity (US$676.5 million in aggregate).

Second Quarter 2025 Operating Results

Sales

Total area committedand pre-committed at the end of the second quarter of 2025 was 663,959 sqm, compared with 614,094 sqm at the end of the second quarterof 2024 and 649,561 sqm at the end of the first quarter of 2025, an increase of 8.1% Y-o-Y and 2.2% quarter-over-quarter (“Q-o-Q”),respectively. In the second quarter of 2025, gross additional total area committed was 22,741 sqm. Net additional total area committedwas 14,398 sqm. The difference is mainly due to a churn of 8,343 sqm of area committed.

Data Center Resources

Area in serviceat the end of the second quarter of 2025 was 618,060 sqm, compared with 580,165 sqm at the end of the second quarter of 2024 and610,685 sqm at the end of the first quarter of 2025, an increase of 6.5% Y-o-Y and 1.2% Q-o-Q.

Area under construction at the end of the secondquarter of 2025 was 132,235 sqm, compared with 117,861 sqm at the end of the second quarter of 2024 and 132,208 sqm at the end of thefirst quarter of 2025, an increase of 12.2% Y-o-Y and remaining flat Q-o-Q, respectively.

Commitment rate for area in service was 91.5%at the end of the second quarter of 2025, compared with 92.3% at the end of the second quarter of 2024 and 90.9% at the end of the firstquarter of 2025. Pre-commitment rate for area under construction was 74.7% at the end of the second quarter of 2025, compared with 66.9%at the end of the second quarter of 2024 and 71.6% at the end of the first quarter of 2025.

Move-In

Area utilized atthe end of the second quarter of 2025 was 479,186 sqm, compared with 419,976 sqm at the end of the second quarter of 2024 and 462,423sqm at the end of the first quarter of 2025, an increase of 14.1% Y-o-Y and 3.6% Q-o-Q. In the second quarter of 2025, gross additionalarea utilized was 22,448 sqm. Net additional area utilized was 16,763 sqm. The difference is mainly due to churn of 5,685 sqm ofarea utilized.

Utilization rate for area in service was 77.5%at the end of the second quarter of 2025, compared with 72.4% at the end of the second quarter of 2024 and 75.7% at the end of the firstquarter of 2025.

Recent Development

Completion of C-REIT IPO and Listing on the Shanghai Stock Exchange

The Company recently announced the launch, pricingand completion of the initial public offering (“IPO”) of its China REIT (C-REIT).

The C-REIT acquired from GDS a 100% equity interestin a project company which holds stabilized data center assets. The acquisition was funded by an IPO on the Shanghai Stock Exchange. Theunits issued by the C-REIT in the IPO were 20% subscribed by GDS, 50% by cornerstone institutional investors in a pre-placement subjectto lock-up commitments of between one to three years, and the remaining 30% through an institutional bookbuilding process and retail publicoffering which were heavily over-subscribed.

The C-REIT issued 800,000,000 units in the IPOat an offering price of RMB3.00 per unit. The total gross proceeds received by the C-REIT was RMB2,400 million. The implied EV / EBITDAat the offering price was 16.9 times, based on projected EBITDA for 2026 of RMB141.8 million as stated in the offering memorandum. Theimplied dividend yield per unit at the offering price was 5.2 per cent, based on projected cash flow available for distribution for 2026of RMB124.8 million as stated in the offering memorandum.

On completion of the sale and purchase of theproject company in late July 2025, GDS is entitled to receive total net cash proceeds of approximately RMB2,073 million net of incometax. GDS has de-consolidated the project company. The net debt and other liabilities (total liabilities net of current assets) were approximatelyRMB30 million at the time of deconsolidation. In conjunction with the sale, GDS concurrently reinvested RMB480 million for 20% of theC-REIT.

The C-REIT started trading on the Shanghai Stock Exchange on August 8,2025 under fund code 508060.

Business Outlook

After taking into consideration the impact ofthe C-REIT transaction which was not included in its original guidance, the Company confirms that the previously provided guidance oftotal revenues for the year of 2025 of RMB11,290 – RMB11,590 million and Adjusted EBITDA of RMB5,190 – RMB5,390 million remainunchanged.

The Company revises its guidance of total capex(investment cashflow) for the year of 2025 down from approximately RMB4,300 million to approximately RMB2,700 million. This comprisesapproximately RMB4,800 million of organic capex (which remains unchanged), less the net cash proceeds received to date of approximatelyRMB500 million from the ABS transaction (which was included in the original guidance), and less the net cash proceeds after reinvestmentof approximately RMB1,600 million from the C-REIT transaction (which was not included in the original guidance).

This forecast reflects the Company’s preliminaryview on the current business situation and market conditions, which are subject to change.

Conference Call

Management willhold a conference call at 8:00 a.m. U.S. Eastern Time on August 20, 2025 (8:00 p.m. Beijing Time on August 20,2025) to discuss financial results and answer questions from investors and analysts.

Participants should complete online registrationusing the link provided below at least 15 minutes before the scheduled start time. Upon registration, participants will receive the conferencecall access information, including dial-in numbers, a personal PIN and an e-mail with detailed instructions to join the conference call.

Participant Online Registration:

https://register-conf.media-server.com/register/BI9125586716a847c3bbf602d1d87b966a

A live and archivedwebcast of the conference call will be available on the Company's investor relations website at investors.gds-services.com.

Non-GAAP Disclosure

Our management and board of directors use AdjustedEBITDA, Adjusted EBITDA margin, Adjusted GP and Adjusted GP margin, which are non-GAAP financial measures, to evaluate our operating performance,establish budgets and develop operational goals for managing our business. We believe that the exclusion of the income and expenses eliminatedin calculating Adjusted EBITDA and Adjusted GP can provide useful and supplemental measures of our core operating performance. In particular,we believe that the use of Adjusted EBITDA as a supplemental performance measure captures the trend in our operating performance by excludingfrom our operating results the impact of our capital structure (primarily interest expense), asset base charges (primarily depreciationand amortization, operating lease cost relating to prepaid land use rights, accretion expenses for asset retirement costs and impairmentlosses of long-lived assets), other non-cash expenses (primarily share-based compensation expenses), and other income and expenses whichwe believe are not reflective of our operating performance (primarily gain or loss on deconsolidation of subsidiaries and share of resultsof equity method investees), whereas the use of adjusted gross profit as a supplemental performance measure captures the trend in grossprofit performance of our data centers in service by excluding from our gross profit the impact of asset base charges (primarily depreciationand amortization, operating lease cost relating to prepaid land use rights and accretion expenses for asset retirement costs) and othernon-cash expenses (primarily share-based compensation expenses) included in cost of revenue. In addition, we exclude the income (loss)from discontinued operation from our Adjusted EBITDA and Adjusted EBITDA margin to measure our financial performance from continuing operations,which will be consistent with our future financial performance disclosure.

We note that depreciation and amortization isa fixed cost which commences as soon as each data center enters service. However, it usually takes several years for new data centersto reach high levels of utilization and profitability. The Company incurs significant depreciation and amortization costs for its earlystage data center assets. Accordingly, gross profit, which is a measure of profitability after taking into account depreciation and amortization,does not accurately reflect the Company’s core operating performance.

We also present these non-GAAP measures becausewe believe these non-GAAP measures are frequently used by securities analysts, investors and other interested parties as measures of thefinancial performance of companies in our industry.

These non-GAAP financialmeasures are not defined under U.S. GAAP and are not presented in accordance with U.S. GAAP. These non-GAAP financial measures have limitationsas analytical tools, and when assessing our operating performance, cash flows or our liquidity, investors should not consider them inisolation, or as a substitute for gross profit, net income (loss), cash flows provided by (used in) operating activities or other consolidatedstatements of operations and cash flow data prepared in accordance with U.S. GAAP. There are a number of limitations related to the useof these non-GAAP financial measures instead of their nearest GAAP equivalent. First, Adjusted EBITDA, Adjusted EBITDA margin, AdjustedGP, and Adjusted GP margin are not substitutes for gross profit, net income (loss), cash flows provided by (used in) operating activitiesor other consolidated statements of operation and cash flow data prepared in accordance with U.S. GAAP. Second, other companies may calculatethese non-GAAP financial measures differently or may use other measures to evaluate their performance, all of which could reduce the usefulnessof these non-GAAP financial measures as tools for comparison. Finally, these non-GAAP financial measures do not reflect the impact ofincome (loss) from discontinued operations, net interest expenses, incomes tax benefits (expenses), depreciation and amortization, operatinglease cost relating to prepaid land use rights, accretion expenses for asset retirement costs, share-based compensation expenses, gainfrom purchase price adjustment, impairment losses of long-lived assets, gain on deconsolidation of subsidiaries and share of results ofequity method investees, each of which have been and may continue to be incurred in our business.

We mitigate theselimitations by reconciling the non-GAAP financial measure to the most comparable U.S. GAAP performance measure, all of which should beconsidered when evaluating our performance. We do not provide forward-looking guidance for certain financial data, such as depreciation,amortization, accretion, share-based compensation, share of results of equity method investees and net income (loss); the impact of suchdata and related adjustments can be significant. As a result, we are not able to provide a reconciliation of forward-looking U.S. GAAPto forward-looking non-GAAP financial measures without unreasonable effort. Such forward-looking non-GAAP financial measures include theforecast for Adjusted EBITDA in the section captioned “Business Outlook” set forth in this press release.

For more information on these non-GAAP financialmeasures, please see the table captioned “Reconciliations of GAAP and non-GAAP results” set forth at the end of this pressrelease.

Exchange Rate

This announcement contains translations of certainRMB amounts into U.S. dollars (“USD”) at specified rates solely for the convenience of the reader. Unless otherwise stated,all translations from RMB to USD were made at the rate of RMB7.1636 to US$1.00, the noon buying rate in effect on June 30, 2025 inthe H.10 statistical release of the Federal Reserve Board. The Company makes no representation that the RMB or USD amounts referred couldbe converted into USD or RMB, as the case may be, at any particular rate or at all.

Statement Regarding Preliminary UnauditedFinancial Information

The unaudited financial information set out inthis earnings release is preliminary and subject to potential adjustments. Adjustments to the consolidated financial statements may beidentified when audit work has been performed for the Company’s year-end audit, which could result in significant differences fromthis preliminary unaudited financial information.

About GDS Holdings Limited

GDS Holdings Limited (NASDAQ: GDS; HKEX: 9698)is a leading developer and operator of high-performance data centers in China. The Company’s facilities are strategically locatedin and around primary economic hubs where demand for high-performance data center services is concentrated. The Company’s data centershave large net floor area, high power capacity, density and efficiency, and multiple redundancies across all critical systems. GDS iscarrier and cloud-neutral, which enables its customers to access the major telecommunications networks, as well as the largest PRC andglobal public clouds, which are hosted in many of its facilities. The Company offers co-location and a suite of value-added services,including managed hybrid cloud services through direct private connection to leading public clouds, managed network services, and, whererequired, the resale of public cloud services. The Company has a 24-year track record of service delivery, successfully fulfilling therequirements of some of the largest and most demanding customers for outsourced data center services in China. The Company’s customerbase consists predominantly of hyperscale cloud service providers, large internet companies, financial institutions, telecommunicationscarriers, IT service providers, and large domestic private sector and multinational corporations. The Company also holds a non-controlling35.6% equity interest in DayOne Data Centers Limited which develops and operates data centers in International markets.

Safe Harbor Statement

This announcementcontains forward-looking statements. These statements are made under the “safe harbor” provisions of the U.S. Private SecuritiesLitigation Reform Act of 1995. These forward-looking statements can be identified by terminology such as “aim,” “anticipate,” “believe,” “continue,” “estimate,” “expect,” “future,” “guidance,” “intend,” “is/are likely to,” “may,” “ongoing,” “plan,” “potential,” “target,” “will,” and similar statements. Among other things, statements that are not historical facts, includingstatements about GDS Holdings’ beliefs and expectations regarding the growth of its businesses and its revenue for the full fiscalyear, the business outlook and quotations from management in this announcement, as well as GDS Holdings’ strategic and operationalplans, are or contain forward-looking statements. GDS Holdings may also make written or oral forward-looking statements in its periodicreports to the U.S. Securities and Exchange Commission (the “SEC”) on Forms 20-F and 6-K, in its current, interim and annualreports to shareholders, in announcements, circulars or other publications made on the website of the Stock Exchange of Hong Kong Limited(the “Hong Kong Stock Exchange”), in press releases and other written materials and in oral statements made by its officers,directors or employees to third parties. Forward-looking statements involve inherent risks and uncertainties. A number of factors couldcause GDS Holdings’ actual results or financial performance to differ materially from those contained in any forward-looking statement,including but not limited to the following: GDS Holdings’ goals and strategies; GDS Holdings’ future business development,financial condition and results of operations; the expected growth of the market for high-performance data centers, data center solutionsand related services in China and regions in which GDS Holdings’ major equity investees operate, such as South East Asia;GDS Holdings’ expectations regarding demand for and market acceptance of its high-performance data centers, data center solutionsand related services; GDS Holdings’ expectations regarding building, strengthening and maintaining its relationships with new andexisting customers; the results of operations, growth prospects, financial condition, regulatory environment, competitive landscape andother uncertainties associated with the business and operations of GDS Holdings’ major equity investee DayOne; the continued adoptionof cloud computing and cloud service providers in China and other major markets that may impact the results of our equity investees, suchas South East Asia; risks and uncertainties associated with increased investments in GDS Holdings’ business and new data centerinitiatives; risks and uncertainties associated with strategic acquisitions and investments; GDS Holdings’ ability to maintain orgrow its revenue or business; fluctuations in GDS Holdings’ operating results; changes in laws, regulations and regulatory environmentthat affect GDS Holdings’ business operations and those of its major equity investees; competition in GDS Holdings’ industryin China and in markets that affect the business operations of its major equity investees, such as South East Asia; GDS Holdings’ability to monetize its existing data center assets through transactions such as public REITs, ABS Scheme, data center funds, joint ventures,sale and lease-back arrangements and private asset sales; security breaches; power outages; and fluctuations in general economic and businessconditions in China and globally, and assumptions underlying or related to any of the foregoing. Further information regarding these andother risks, uncertainties or factors is included in GDS Holdings’ filings with the SEC, including its annual report on Form 20-F,and with the Hong Kong Stock Exchange. All information provided in this press release is as of the date of this press release and arebased on assumptions that GDS Holdings believes to be reasonable as of such date, and GDS Holdings does not undertake any obligation toupdate any forward-looking statement, except as required under applicable law.

For investor and media inquiries, please contact:

GDS Holdings Limited

Laura Chen

Phone: +86 (21) 2029-2203

Email: ir@gds-services.com

Piacente Financial Communications

Ross Warner

Phone: +86 (10) 6508-0677

Email: GDS@tpg-ir.com

Brandi Piacente

Phone: +1 (212) 481-2050

Email: GDS@tpg-ir.com

GDS Holdings Limited

GDS HOLDINGS LIMITED

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS

(Amount in thousands of Renminbi ("RMB")and US dollars ("US$"))

GDS HOLDINGS LIMITED

UNAUDITED CONDENSED CONSOLIDATED STATEMENTSOF OPERATIONS

(Amount in thousands of Renminbi ("RMB")and US dollars ("US$")

except for number of shares and per share data)

GDS HOLDINGS LIMITED

UNAUDITED CONDENSED CONSOLIDATED STATEMENTSOF COMPREHENSIVE (LOSS) INCOME

(Amount in thousands of Renminbi ("RMB")and US dollars ("US$"))

GDS HOLDINGS LIMITED

UNAUDITED CONDENSED CONSOLIDATED STATEMENTSOF CASH FLOWS

(Amount in thousands of Renminbi ("RMB")and US dollars ("US$"))

GDS HOLDINGS LIMITED

RECONCILIATIONS OF GAAP AND NON-GAAP RESULTS

(Amount in thousands of Renminbi ("RMB")and US dollars ("US$")

except for percentage data)

GDS HOLDINGS LIMITED

RECONCILIATIONS OF GAAP AND NON-GAAP RESULTS

(Amount in thousands of Renminbi ("RMB")and US dollars ("US$")

except for percentage data)