Exhibit 99.1

RECONCILIATION BETWEEN U.S. GENERALLY ACCEPTED ACCOUNTING PRINCIPLES (“U.S. GAAP”) AND IFRS ACCOUNTING STANDARDS (“IFRS”)

The unaudited interim condensed consolidated financial information for the six months ended June 30, 2025 of GDS Holdings Limited (the “Company”) are prepared under U.S. Generally Accepted Accounting Principles (“U.S. GAAP”) and reviewed by the Audit Committee of the Board.

Basis of Preparation

The Directors of the Company are responsible for preparing the Company’s reconciliation statement in relation to the effects of material differences between the Company’s financial information prepared under U.S. GAAP and IFRS Accounting Standards (“IFRS”) as of and for the six months ended June 30, 2025 (the “Reconciliation Statement”) in accordance with the relevant requirements of the Listing Rules and relevant guidance in HKEX-GL111-22. The Reconciliation Statement comprises a reconciliation setting out the financial effect of material differences between the Company’s accounting policies under U.S. GAAP and IFRS, and an explanation of such differences.

Reconciliation Process

The process applied in the preparation of Reconciliation Statement includes:

Limited Assurance Engagement and Results

KPMG was engaged by the Company to conduct work on the Reconciliation Statement and to report thereon in the form of an independent limited assurance conclusion to the Directors based on the evidence obtained in accordance with Hong Kong Standard on Assurance Engagements 3000 (Revised) Assurance Engagements Other Than Audits or Reviews of Historical Financial Information (“HKSAE 3000 (Revised)”) issued by the Hong Kong Institute of Certified Public Accountants (the “HKICPA”).

A limited assurance engagement consists of making inquiries, primarily of persons responsible for the preparation of the Reconciliation Statement, assessing the suitability of the basis of preparation and the reconciliation process, and applying other procedures. The procedures selected depend on their understanding of the Reconciliation Statement and other engagement circumstances, and the consideration of areas where material misstatements are likely to arise. These procedures included:

RECONCILIATION BETWEEN U.S. GENERALLY ACCEPTED ACCOUNTING PRINCIPLES (“U.S. GAAP”) AND IFRS ACCOUNTING STANDARDS (“IFRS”)

The procedures performed in a limited assurance engagement vary in nature and timing from, and are less in extent than for, a reasonable assurance engagement. Consequently, the level of assurance obtained in a limited assurance engagement is substantially lower than the assurance that would have been obtained had a reasonable assurance engagement been performed.

KPMG’s engagement did not involve independent examination of any of the underlying records or other sources from which the Reconciliation Statement was extracted. The procedures performed in accordance with HKSAE 3000 (Revised) is different in scope from an audit or a review conducted in accordance with Hong Kong Standards on Auditing or Hong Kong Standards on Review Engagements issued by the HKICPA and consequently, KPMG did not express an audit opinion nor a review conclusion on the Reconciliation Statement. KPMG’s engagement was intended solely for the use of the Directors in connection with the Company’s interim report for the six months ended 30 June, 2025 and may not be suitable for another purpose. Based on the procedures performed and evidence obtained, nothing has come to KPMG’s attention that causes them to believe:

RECONCILIATION BETWEEN U.S. GENERALLY ACCEPTED ACCOUNTING PRINCIPLES (“U.S. GAAP”) AND IFRS ACCOUNTING STANDARDS (“IFRS”)

The Company's unaudited interim condensed consolidated financial information are prepared in accordance with U.S. GAAP, which differ in certain respects from IFRS. The effects of material differences between U.S. GAAP and IFRS are as follows:

RECONCILIATION BETWEEN U.S. GENERALLY ACCEPTED ACCOUNTING PRINCIPLES (“U.S. GAAP”) AND IFRS ACCOUNTING STANDARDS (“IFRS”)

RECONCILIATION BETWEEN U.S. GENERALLY ACCEPTED ACCOUNTING PRINCIPLES (“U.S. GAAP”) AND IFRS ACCOUNTING STANDARDS (“IFRS”)

RECONCILIATION BETWEEN U.S. GENERALLY ACCEPTED ACCOUNTING PRINCIPLES (“U.S. GAAP”) AND IFRS ACCOUNTING STANDARDS (“IFRS”)

RECONCILIATION BETWEEN U.S. GENERALLY ACCEPTED ACCOUNTING PRINCIPLES (“U.S. GAAP”) AND IFRS ACCOUNTING STANDARDS (“IFRS”)

Notes:

Under U.S. GAAP, there is a dual-classification lease accounting model for lessees: finance leases and operating leases. For operating leases, unless the right-of-use asset has been impaired, the amortization of right-of-use assets and the interest expense of lease liabilities are recorded together as a single lease cost on a straight-line basis over the remaining lease term.

Under IFRS, all leases are classified as finance leases, where right-of-use assets are amortized on a straight-line basis, while interest expense of lease liabilities are recorded in interest expenses under the effective interest method, which generally yields a “front-loaded” expense with more expense recognized in earlier years of the lease.

Under U.S. GAAP, Convertible Bonds due 2029 and 2030 of the Company are classified as liabilities and measured at amortized cost, with any difference between the initial carrying value and the repayment amount recognized as interest expenses using effective interest method over the period from the issuance date to the maturity date.

Under IFRS, Convertible Bonds due 2029 and 2030 of the Company are divided into liability and equity components with the initial value of the liability component being the present value of a straight bond and the remaining value allocated to the equity component. The issuance cost is allocated between the liability and equity components. The liability component of the convertible bonds is subsequently measured at amortized cost using the effective interest rate method.

Under U.S. GAAP, Convertible Bonds due 2032 of the Company are classified as liabilities and measured at amortized cost, with any difference between the initial carrying value and the repayment amount recognized as interest expenses using effective interest method over the period from the issuance date to the maturity date.

Under IFRS, Convertible Bonds due 2032 of the Company are divided into derivative and non-derivative liability components with the initial value of the derivative component being the fair value and the remaining value allocated to the non-derivative liability component. The issuance cost is allocated between the derivative and non-derivative components. The portion allocated to the derivative component is recognized as expense immediately. The derivative component is subsequently measured at fair value with changes in fair value recognized in profit or loss. The non-derivative liability component of the convertible bonds is subsequently measured at amortized cost using the effective interest rate method.

RECONCILIATION BETWEEN U.S. GENERALLY ACCEPTED ACCOUNTING PRINCIPLES (“U.S. GAAP”) AND IFRS ACCOUNTING STANDARDS (“IFRS”)

Under U.S. GAAP, the redeemable preferred shares of the Company are classified as mezzanine equity since they are redeemable at the option of the holder. The issuance cost is treated as an adjustment to the initial value of the redeemable preferred shares of the Company. The redeemable preferred shares of the Company are subsequently accreted to the redemption value using effective interest rate.

Under IFRS, the redeemable preferred shares of the Company are divided into derivative component, non-derivative liability component and equity component with the initial value of the derivative component being the fair value, the initial value of the non-derivative liability component referring the present value of a straight debt and the remaining value allocated to the equity component. The issuance cost is allocated among the derivative, the non-derivative liability and the equity components. The non-derivative liability component of the redeemable preferred shares of the Company is subsequently amortized using effective interest rate.

Under U.S. GAAP, when the non-controlling interests are redeemable at the option of the non-controlling shareholder, or contingently redeemable upon the occurrence of a conditional event that is not solely within the control of the Company, the non-controlling interests are separately classified as mezzanine equity. As a result, the Series A Preferred Shares issued by DayOne, which were redeemable non-controlling interests, were classified as mezzanine equity and initially measured at fair value. Since the redemption was not considered probable, they were subsequently measured pursuant to ASC 810 (i.e. increased or decreased for the non-controlling interests’ share of net income or loss).

Under IFRS, the Series A Preferred Shares issued by DayOne were bifurcated into liability and equity components. The liability component was measured at redemption value and the equity component was measured at the residual amount. The liability component was subsequently amortized using effective interest rate.

The balance of redeemable preferred shares of DayOne was derecognized upon deconsolidation of DayOne. The difference in carrying value of the mezzanine equity recognized under U.S. GAAP and the liability under IFRS upon deconsolidation was reflected in gain on deconsolidation of subsidiaries.

RECONCILIATION BETWEEN U.S. GENERALLY ACCEPTED ACCOUNTING PRINCIPLES (“U.S. GAAP”) AND IFRS ACCOUNTING STANDARDS (“IFRS”)

Under U.S. GAAP, when the non-controlling interests are redeemable at the option of the non-controlling shareholder, or contingently redeemable upon the occurrence of a conditional event that is not solely within the control of the Company, the non-controlling interests are separately classified as mezzanine equity. If the redemption is not considered probable, they are subsequently measured pursuant to ASC 810 (i.e. increased or decreased for the non-controlling interests’ share of net income or loss). If the redemption is considered probable, they are subsequently measured as the greater of (i) the balance determined pursuant to ASC 810 and (ii) the balance determined pursuant to ASC 480-10-S99-3A (i.e. the redemption value, which cannot be lower than initial amount). As the redemption was considered probable, the subsequent accretion to redemption value of the redeemable non-controlling interests was charged against additional paid-in capital.

Under IFRS, the redeemable non-controlling interests, other than the Series A Preferred Shares of DayOne, were presented as liability, as the Company did not have the unconditional right to avoid delivering cash or another financial asset, and measured at fair value subsequently. The changes in the fair value were subsequently recognized in profit or loss.

Under U.S. GAAP, two-step approach is used in the measurement and recognition of impairment loss of long-lived assets. During step one, recoverability test, the carrying amount is first compared with the undiscounted cash flows, using entity specific assumptions. During step two, measurement test, if the carrying amount is higher than the undiscounted cash flows, an impairment loss is measured as the difference between the carrying value and fair value. Subsequent reversal of a previously recognized impairment loss is prohibited.

Under IFRS, a one-step approach is used in impairment testing. The carrying amount is compared with the recoverable amount, which is the higher of fair value less costs of disposal or the asset’s value in use based on the net present value of future cash flows. Therefore, the difference in impairment assessment results in difference in impairment loss under IFRS. In addition, the lease accounting difference leads to difference in the carrying amounts of right-of-use assets and thus results in difference in impairment loss. If there is an indication of reversal of impairment for a long-lived asset and the recoverable amount of the impaired asset or cash generating unit increases subsequently, then the impairment loss is generally reversed. A reversal of an impairment loss is generally recognized in profit or loss.

Under both U.S. GAAP and IFRS, when the Company reorganizes its reporting structure in a manner that changes the composition of one or more of its reporting units, or when a portion of a reporting unit that constitutes a business is to be disposed of, goodwill is reassigned to the reporting units affected using a relative fair value allocation approach. The differences in goodwill balance and the relative fair value of reporting units between U.S. GAAP and IFRS lead to the difference in allocation of goodwill and gain on deconsolidation of subsidiaries.

RECONCILIATION BETWEEN U.S. GENERALLY ACCEPTED ACCOUNTING PRINCIPLES (“U.S. GAAP”) AND IFRS ACCOUNTING STANDARDS (“IFRS”)

Under both U.S. GAAP and IFRS, non-current assets and some groups of assets and liabilities (“disposal groups”) are classified as held-for-sale if their carrying amounts will be recovered principally through sale and specific criteria related to their sale are met, and the held for sale assets include the goodwill which is reassigned to the reporting units to be disposed of using a relative fair value allocation approach. The differences in goodwill balance and the relative fair value of reporting units between U.S. GAAP and IFRS lead to the difference in allocation of goodwill and the balance of held for sale assets.

Under both U.S. GAAP and IFRS, equity method is used to account for the investments in equity investees if the Company has significant influence but does not have control over the investee. The differences in the results of the investees are caused by the differences in accounting treatment of transactions such as leases and long-lived assets impairment under U.S. GAAP and IFRS, which lead to differences in share of results of equity method investees and the balances of long-term investments in equity investees.