AMERICAN TOWER CORP /MA/ (AMT) · Insider Trading (Form 4) SEC Filing

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-03-10 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: AMERICAN TOWER CORP /MA/ (AMT) CIK: 0001053507 --- Reporting Owner --- Name: Rossi Richard C CIK: 0002053262 Role: Officer (EVP & President, U.S. Tower) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-03-10 | Code: A (Grant or award) Shares: +6,448 | Price: $0.00 Shares Owned After: 19,746 | Ownership: D (Direct) Footnotes: [F1] These restricted stock units ("RSUs") were granted pursuant to the 2007 Equity Incentive Plan, as amended (the "Plan"), and vest 1/3rd annually over three years, commencing one year from the date of grant. Each RSU represents a contingent right to receive one share of Common Stock. [F2] Includes 80 and 40 shares acquired under the issuer's employee stock purchase plan in May 2025 and November 2025, respectively. [Transaction #2] Security: Common Stock Date: 2026-03-10 | Code: F (Payment of exercise/tax) Shares: -1,544 | Price: $186.12 Total Value: $287,369.28 Shares Owned After: 18,202 | Ownership: D (Direct) Footnotes: [F3] Shares delivered to the issuer for the payment of withholding taxes in connection with the vesting of RSUs previously granted under the Plan. [Transaction #3] Security: Common Stock Date: 2026-03-11 | Code: F (Payment of exercise/tax) Shares: -684 | Price: $182.85 Total Value: $125,069.40 Shares Owned After: 17,518 | Ownership: D (Direct) Footnotes: [F3] Shares delivered to the issuer for the payment of withholding taxes in connection with the vesting of RSUs previously granted under the Plan. --- Footnotes (Complete Index) --- F1: These restricted stock units ("RSUs") were granted pursuant to the 2007 Equity Incentive Plan, as amended (the "Plan"), and vest 1/3rd annually over three years, commencing one year from the date of grant. Each RSU represents a contingent right to receive one share of Common Stock. F2: Includes 80 and 40 shares acquired under the issuer's employee stock purchase plan in May 2025 and November 2025, respectively. F3: Shares delivered to the issuer for the payment of withholding taxes in connection with the vesting of RSUs previously granted under the Plan. --- Signature --- /s/ /s/ Marina A. Breed, as attorney-in-fact (2026-03-12)