American Tower (AMT) Proxy filing summary

Board of directors and corporate governance

• Board held four regular and five special meetings during fiscal year 2025.

• Each Director attended at least 75% of Board meetings; committee attendance was at least 75% except for Directors who joined committees mid-year.

• Ms. Clarke attended 100% of Audit Committee and 67% of Nominating Committee meetings after joining the latter in May 2025.

• Mr. Reilly attended 50% of Compensation Committee meetings after joining in August 2025.

• All Director nominees serving as of the 2025 Annual Meeting attended that meeting.

Voting matters and shareholder proposals

• Board recommends voting “FOR” all Director nominees named in the Proxy Statement.

• No changes to proposals or Board recommendations as a result of this supplement.

Shareholder rights and capital structure

• Shareholders may change or revoke prior votes by following instructions provided in the Proxy Statement.