AMERICAN TOWER CORP MA

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Stockholders and the Board of Directors of American Tower Corporation

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of American Tower Corporation and subsidiaries (the “Company”) as of December 31, 2024 and 2023, the related consolidated statements of operations, comprehensive income, equity, and cash flows, for each of the three years in the period ended December 31, 2024, and the related notes and the schedule listed in the Index at Item 15 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control — Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 25, 2025, expressed an unqualified opinion on the Company's internal control over financial reporting.

Basis for Opinion

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Change in estimated useful life of tower assets - Refer to Notes 1, 3, 4, and 5 to the financial statements.

Critical Audit Matter Description

As described in Note 1 to the financial statements, the Company finalized its review of the estimated useful lives of its tower assets, effective as of January 1, 2024. The Company determined that the estimated useful life of its tower assets should be changed from 20 years to 30 years. Additionally, consistent with the useful life of the tower assets, the Company changed the useful life of certain intangible assets as well as lease terms used to measure the right of use assets and lease liabilities.

The Company accounted for the change in useful life as a change in accounting estimate and applied the change on a prospective basis beginning on January 1, 2024. Accordingly, the Company began depreciating its tower assets and amortizing certain intangible assets over the extended useful life. The change in useful life resulted in (i) a $515 million increase to the right of use assets and related lease liabilities as of January 1, 2024 and (ii) an estimated $730 million decrease in depreciation and amortization expense for the year ended December 31, 2024.

We identified the change in estimated useful life of tower assets as a critical audit matter due to the significant judgments made by management to support the useful life of the tower assets. There was a high degree of auditor judgment in evaluating management’s assumptions and estimates and required the assistance of valuation specialists to validate the appropriateness of assumptions made by management.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to the change in estimated useful life of tower assets included the following, among others:

•We inquired of management and operations and engineering personnel to understand the process to build, inspect, and maintain tower assets.

•We inquired of management’s independent consultant to understand the processes and procedures that were used to develop the revised estimates of useful life.

•We utilized our fair value specialists that possess relevant engineering expertise to assist us with:

◦Assessing the technical specifications of the Company’s towers and the Company’s operating procedures, as those specifications and procedures impact the useful life of the towers.

◦Performing independent research on the useful life of towers.

•For a selection of countries, we tested the completeness and accuracy of the tower data used by the Company in supporting the change in estimated useful life.

•We tested the effectiveness of internal controls over the development of the estimates of the useful life of the tower assets and the controls over measuring and recognizing the financial statement impacts of the change in estimate.

•With the assistance of professionals in our firm having expertise in lease accounting, we evaluated the Company’s conclusions regarding the accounting for the impact of the change in estimated useful life of the tower assets on the right of use assets and operating lease liabilities.

/s/Deloitte & Touche LLP

Boston, Massachusetts

February 25, 2025

We have served as the Company’s auditor since 1997.