AMERICAN TOWER CORP MA

The following pages provide a summary of important information you will find in this Proxy Statement. As it is only a summary, please review the complete Proxy Statement before submitting your vote.

Proposals To Be Voted On and Our Board's Recommendations

American Tower’s Strategy and Vision

To strategically partner with our customers to strengthen our global leadership position as an owner, operator and developer of multitenant, neutral-host digital infrastructure—deploying our capital to add scale to our core business, selectively extending our product platform, developing our talent and creating a sustainable culture that both drives returns for our stockholders and bridges the digital divide.

American Tower’s Key Objectives Support Our Vision of “Building a More Connected World.”

Company Overview

American Tower (the Company) is a leading independent owner, operator and developer of wireless and broadcast communications real estate.

As of December 31, 2023, our global portfolio of over 224,000 communications sites(1)(2) includes:

•~43,000 sites in the U.S. and Canada; and

•181,000+ sites(2) in international markets.

Our portfolio of communications infrastructure assets includes other telecommunications assets, including:

•28 data center facilities across 10 U.S. markets.

(1)Includes distributed antenna systems (DAS).

(2)In January 2024, we entered into an agreement to sell 100% of the equity interests in our operations in India, a transaction that is expected to close in the second half of 2024, subject to customary closing conditions, including government and regulatory approval. As of December 31, 2023, our portfolio consists of nearly 77,000 communications sites in India.

2023 Business Highlights

KEY FINANCIAL RESULTS(1)

•Grew total revenue by approximately 4.0% to $11.1 billion, grew property revenue(2) by approximately 5.1% to $11.0 billion, net income decreased by approximately 19.4% to $1.4 billion(3) and grew Adjusted EBITDA(2)by approximately 6.7% to $7.1 billion;

•Had record colocation and amendment growth in both our U.S. & Canada property segment and our international segment and a second consecutive year of record sales in our Data Centers segment;

•Declared over $3.0 billion in cash dividends to common stockholders;

•Deployed approximately $1.8 billion in capital expenditures in 2023, with the majority of spending on growth-oriented, discretionary investments;

•AFFO attributable to AMT common stockholders per Share (AFFO Attributable per Share)(4) was $9.87 and ROIC(4) was 9.3% for the full year; and

•Maintained our investment-grade credit rating and de-levered our balance sheet, ending the year with a Net Leverage Ratio of 5.2x.

(1)Adjusted EBITDA, AFFO Attributable per Share and ROIC are non-GAAP financial measures. Definitions of non-GAAP financial measures and reconciliations to GAAP can be found in Appendix A.

(2)Performance metric under the annual performance incentive program. For the total property revenue performance metric, pass-through revenue is excluded.

(3)Growth rate impacted by foreign currency losses of approximately $331 million in 2023 as compared to foreign currency gains of approximately $449 million in 2022.

(4)Performance metric under the long-term incentive program.

Our Director Nominees

With the exception of Messrs. Thomas A. Bartlett, Raymond P. Dolan and Samme L. Thompson, each incumbent Director is standing for re-election at our 2024 Annual Meeting of Stockholders (the Annual Meeting). You are being asked to vote on the election of 11 Directors, all of whom were recommended for nomination to the Board of Directors (Board) by the Nominating and Corporate Governance Committee (Nominating Committee). All Directors are elected annually by a majority of votes cast. Detailed information about each Director’s background, skill set and areas of expertise can be found beginning on page 12.

Board Diversity

Each of our Board Committees consists of at least one female director and one director who identifies as part of a racial or ethnic minority group.

Our Corporate Governance Guidelines provide for the Nominating Committee to consider elements of background that incorporate diversity, including differences in skills, professional backgrounds and demographics such as gender, race, ethnicity, national origin, age, sexual orientation and gender identity. We are committed to board diversity and are proud of our leadership in this over the past decade. Our Board consists of individuals with diverse and complementary business, leadership and financial expertise. Most of our Directors have leadership experience at major U.S. and multinational companies, as well as experience on the boards of other companies and organizations, which provides an understanding of different business processes, challenges and strategies. In addition, many of our Directors have industry and public policy experience, which provides insight into issues faced by public companies.

Board Refreshment

(1)Including Messrs. Dolan and Thompson, who will not be standing for re-election at this year’s Annual Meeting.

Corporate Governance Best Practices

Sustainability Highlights

At American Tower, we are helping to build a more connected world while simultaneously generating value for our stockholders. Our business inherently promotes sustainability through the reduced environmental footprint of shared infrastructure. Our commitment extends beyond environmental impact mitigation to encompass respect for individuals, foster social equity, uphold business ethics and drive continuous enhancement of our business performance.

Our sustainability framework is built on three pillars: environment, social and governance, each pivotal in our vision of building a more connected world.

ENVIRONMENT

At American Tower, we recognize our responsibility to contribute to the global mitigation of climate change and, as such, we are actively working to reduce our greenhouse gas (GHG) emissions.

We have invested over $600 million since 2012 in our three-pronged strategy to reduce GHG emissions, which includes (i) energy efficiency improvements, (ii) renewable energy procurement and on-site generation and (iii) sophisticated energy storage systems.

SOCIAL

2023 Employee Survey Results

In 2023, employees were sent our biennial employee engagement survey. The survey was completed by 88% of our employees, and select participation results are noted below:

Connecting Communities

Our commitment to digital inclusion is embodied in our Digital Communities program, which is designed to bridge the digital divide by establishing digitally connected spaces in underserved communities equipped with technology offering various learning tools and services. As of December 31, 2023, we have launched more than 580 Digital Communities, which have served more than 720,000 people across 15 countries.

GOVERNANCE

The Nominating Committee oversees the Company’s annual sustainability reporting process. Additionally, with oversight from our Board, our executive team leads our global operations with a firm commitment to doing business in an ethical and sustainable manner.

Executive Compensation Philosophy

Say on Pay

Our stockholders have historically approved our say-on-pay proposal at a high rate, with approximately 96% of votes cast in favor of our executive compensation program at our 2023 annual meeting of stockholders.

Framework of 2023 Compensation

Executive Pay Structure

(1)Beginning in 2024, PSU awards granted under our long-term incentive award program will include relative Total Shareholder Return (TSR) as an additional performance measure for a three-year performance period.

(2)AFFO Attributable per Share and ROIC are non-GAAP financial measures. Definitions of non-GAAP financial measures and reconciliations to GAAP can be found in Appendix A.