AMERICAN TOWER CORP MA

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

(Rule 14a-101)

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No. )

Filed by the Registrantx Filed by a Party other than the Registrant ☐

Check the appropriate box:

Dear Stockholder:

April 10, 2024

It is my pleasure to invite you to American Tower Corporation’s 2024 Annual Meeting of Stockholders on Wednesday, May 22, 2024 at 11:00 a.m. Eastern Time. We will hold the Annual Meeting virtually through a live audio webcast. You will be able to attend the meeting by visitingwww.virtualshareholdermeeting.com/AMT2024. Please follow the instructions in this Proxy Statement to join the virtual Annual Meeting.

Included with this letter are the official notice of meeting; the Proxy Statement, which describes in detail the matters to be discussed and voted on at the meeting; and the form of proxy.

Your vote is important. You may vote your shares online; by telephone; by mail, if you received a paper copy of the proxy materials and follow the instructions on the proxy card or voting instruction card; or at the virtual meeting. If you vote by proxy prior to the meeting, you may withdraw your proxy and vote at the virtual meeting, if you wish to do so. Whether or not you plan to attend the meeting, I urge you to vote as soon as possible to ensure your shares will be represented at the meeting.

On behalf of the executive team and your Board of Directors, I thank you for your continued support.

Sincerely,

Steven O. Vondran

President and Chief Executive Officer

Letter From the Independent Chairperson of the Board

April 10, 2024

Dear Fellow Stockholders,

It's a privilege to write to you once again as the Chairperson of the Board at American Tower. 2023 was a year of significant challenge, resilient performance and transition at the Company. Despite a difficult macro-economic backdrop and operating environment, our teams delivered record new business growth across our U.S. & Canada, International and Data Centers segments, drove compelling margin expansion and returned approximately $3 billion to stockholders through common share distributions, all while navigating inflation and interest rate headwinds.

Succession planning and talent management are at the core of our responsibility to you. As we announced late last year, Tom Bartlett retired as President and CEO effective this past February and will be retiring from the Company in May. I'd like to thank Tom for his decade and a half of dedicated leadership at the Company and congratulate him on an outstanding career. We also announced that Steve Vondran would be succeeding Tom as President and CEO of the Company. As the Board embarked on an extensive CEO search, Steve emerged as the clear candidate to lead us into the future. Over the past few decades, including over 20 years with the Company, he has established himself as leader and innovative thinker, both within American Tower and across the industry. Steve's succession to the CEO role is a testament to the depth of talent and expertise on our leadership team, and as stockholders, we're in great hands with Steve at the helm.

As we look forward to our next stage of evolution as a company, Steve, his team and the Board remain committed to creating long-term value for stockholders. With that goal in mind, and based on feedback from you, beginning in 2024, PSU awards granted under our long-term incentive program will include relative Total Shareholder Return (TSR) as an additional performance measure for executive compensation. In addition, management and the Board are aligned on several key areas of focus as we look to 2024 and beyond. Below are a few highlights.

Leverage our Scale to Maximize Growth and Profitability

Over the past two plus decades, we've amassed a leading portfolio of tower and data center assets in the most attractive geographies across the globe, where secular demand trends suggest the potential for long-term, sustainable growth. We're now positioned to harvest the benefits of the scale we've developed. To execute on that opportunity, we're focused on maximizing organic growth by continuing to secure business with market leaders, staying disciplined when it comes to contract structures that drive upside and mitigate identifiable risks and leveraging our global operating expertise to expand value accretive offerings like build-to-suits and Power-as-a-Service. At the same time, the team is focused on developing the most efficient operating model and delivering best-in-class profitability. We've made significant strides in recent years by globalizing our operations and taking costs out of the business, and maximizing the conversion of top-line growth to the bottom-line is going to be a core focus going forward.

Balance Sheet Strength & Disciplined Capital Allocation

We made substantial progress toward strengthening our balance sheet and getting within reach of our leverage target in 2023. Positioning our balance sheet as a strategic asset and maintaining an investment grade credit rating are both at the heart of our strategy, as we firmly believe market access and cost of capital advantages are going to be critical in the next cycle. This goes hand-in-hand with managing a disciplined capital allocation program that's flexible and focused on expanding our tower and data center platforms by re-investing cash flows in opportunities with the highest risk adjusted rates of return, and that support strong, sustainable earnings growth.

Investing in our Communities

Importantly, we're committed to investing in the communities we serve and creating value for all of our stakeholders. This is best exemplified through our signature Digital Communities philanthropic program. Our Digital Communities are focused on bridging the digital divide by providing connected spaces in underserved areas. These centers, often developed in partnership with our customers, provide instructor or self-led digital literacy, youth education instruction, financial literacy, healthcare and other services to support quality of life and economic opportunity in our communities, and these services have now reached more than 720,000 people across 15 countries. We're proud of the contributions we've made to date, and are committed to continuing to expand our impact.

Board Diversity and Refreshment

To close, I would be remiss if I did not take the opportunity to thank Ray Dolan and Samme Thompson for their years of service on the Board of Directors. I'd also like to welcome Neville Ray, who joined the Board of Directors in March of this year. Our Directors believe a board with diverse skills, experience and viewpoints is critical to the Company's long-term success. Neville will provide our Board with fresh perspectives, as well as his extensive experience as a leader in the wireless communications industry.

Finally, I'd like to thank you, our stockholders, for your ongoing support. We look forward to continuing to collaborate and create value with you for many years to come.

Sincerely,

Pamela D. A. Reeve

Independent Chairperson of the Board

Notice of 2024 Annual Meeting of Stockholders

At the Annual Meeting you will be asked to:

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