AMERICAN TOWER CORP /MA/

Our NEOs are eligible for benefits under the terms of our severance program and applicable equity award agreements (collectively, the Severance Program). The table below, “Potential Payments Upon Termination or Change of Control for 2025,” summarizes the severance benefits that would be payable to each of our NEOs if his or her employment had been terminated as of December 31, 2025, with respect to the different termination scenarios. Under the Severance Program, our executive officers are entitled to the following severance benefits upon a Qualifying Termination:

•Cash Severance: The CEO is entitled to receive 104 weeks of base earnings, and each Executive Vice President is entitled to receive 78 weeks of base earnings. In addition, each executive would be entitled to a pro-rated portion of his or her target incentive for the portion of the year prior to termination, assuming 100% satisfaction of goals or objectives related to that incentive.

•Equity Acceleration/Vesting Provisions: If a Qualifying Termination occurs within 14 days prior to, or up to two years following, a Change of Control, each executive officer is entitled to acceleration of vesting of certain outstanding stock options, RSUs and PSUs, as further described below.

•Benefits Continuation: Each executive officer is eligible for continued health and welfare benefits, for which the Company will pay the employer share of the cost of coverage for a period equal to the number of weeks of base earnings payable under the Severance Program and, subject to eligibility, is entitled to benefits under the Consolidated Omnibus Budget Reconciliation Act.

•Release of Claims, Non-Compete: To receive benefits under our Severance Program, the executive officer must sign a separation and release agreement and a limited confidentiality and restrictive covenant agreement in forms satisfactory to the Company. In addition, at our discretion, we may require the deposit of a portion of the after-tax payments to each executive officer in a restricted account to serve as security for the executive officer’s compliance with the ongoing covenants, restrictions and obligations contained in such agreements, with restrictions on distribution up to and including forfeiture in the event of noncompliance.

Under our Severance Program, equity awards to our executive officers are subject to a double-trigger standard, whereby the executive officer is entitled to acceleration of his or her equity awards only in the event of a Qualifying Termination within 14 days before, or two years following, a Change of Control. In such an event, the executive officer is entitled to acceleration of all unvested equity-based awards, including stock options and RSUs, which are paid within 60 days of the scheduled vesting date. With respect to the grant of PSUs, the value of those PSUs would be determined based on target performance, pro-rated for the executive’s term of employment during the performance period prior to the Qualifying Termination (except for PSUs granted to executive officers that are eligible for a “Qualified Retirement” (as defined in the award agreement), with respect to which the target award is accelerated in full (i.e., no pro-ration is applied)) and paid out within 60 days of the Qualifying Termination, unless such executive officer is a “specified employee” as defined in the Treasury Regulation Section 1.409A-1(i). If there is no Qualifying Termination or if the termination is a Qualifying Termination not in connection with a Change of Control, the executive officer is not entitled to any acceleration or continued vesting of his or her equity-based awards, except in connection with a Qualified Retirement. The Severance Program does not provide for tax gross-ups.

In addition, the Compensation Committee adopted a death, disability and retirement benefits program in connection with equity awards granted to our employees, including executive officers, similar to those of our peer group companies. The program’s benefits provide for the acceleration of vesting and exercise periods for stock options, RSUs and PSUs granted on or after January 1, 2013, upon an employee’s death or permanent disability, or upon an employee’s Qualified Retirement, provided certain eligibility criteria are met.

Our NEOs are also eligible to receive nine months of outplacement services following a Qualifying Termination.

POTENTIAL PAYMENTS UPON TERMINATION OR CHANGE OF CONTROL FOR 2025

The table below sets forth the potential estimated payments pursuant to our Severance Program to each NEO as if the individual’s employment had been terminated as of December 31, 2025. While our executive officers are entitled to certain severance benefits upon a Qualifying Termination pursuant to the terms of the Severance Program, acceleration of vesting of outstanding equity-based awards is limited to a Qualifying Termination upon a Change of Control, subject to earlier vesting under the death, disability and retirement program.

(1)Awards are accelerated in full only if the Qualified Retirement occurs after the date that is six months from the date of grant of such award, and upon successful completion of a transition plan with the Company. Awards granted within the six month time period are cancelled. If a transition plan is not entered into, or is not successfully completed, acceleration will be prorated pursuant to the terms of the Severance Program.

(2)For Mr. Vondran, the amount reflects salary continuation for 104 weeks, based on Mr. Vondran’s base salary as of December 31, 2025. For Messrs. Smith, Puech and Noel and Ms. Dowling, the amount reflects salary continuation for 78 weeks, based on base salary as of December 31, 2025. The Severance Program specifies that continuation of salary is to be paid bi-weekly.

(3)This amount reflects an incentive award opportunity with respect to a full year of service for the year ended December 31, 2025 and assumes that a bonus target of 100% is met. Actual incentive award payments upon separation are calculated pro-rata. For the year ended December 31, 2025, the bonus target was 200% of base salary for Mr. Vondran and was 125% of base salary for Messrs. Smith, Puech and Noel and Ms. Dowling.

(4)Value of RSUs and PSUs is determined using the closing market price of $175.57 of our Common Stock on December 31, 2025.

(5)As of December 31, 2025, under the Severance Program, each executive officer is entitled to acceleration of vesting of certain outstanding equity-based awards, including, but not limited to, stock options, RSUs and PSUs, upon a Qualifying Termination that occurs within 14 days prior to, or up to two years following, a Change of Control, as described above.

(6)In addition to the acceleration of vesting of certain outstanding equity-based awards upon a Qualifying Termination in connection with a Change of Control under the Severance Program (as described above), equity-based awards that were granted after January 1, 2013 will vest upon their Qualifying Retirement, death or permanent disability, pursuant to the terms of the Company’s death, disability and retirement program (as described above). In accordance with the revised executive officer retirement benefits, the values of the PSU awards assume successful completion of a transition plan and reflect full payout of PSUs at target. NEOs are not entitled to accelerated vesting of equity-based awards upon a voluntary termination other than as described in this Footnote 6.

(7)For Mr. Vondran, this amount reflects a continuation of health and dental insurance for 104 weeks, based on the employer share of the cost of coverage for this time period. For Messrs. Smith, Puech and Noel and Ms. Dowling, this amount reflects a continuation of health and dental insurance for 78 weeks, based on the employer share of the cost of coverage for this time period. All amounts are estimates based on current rates and benefits elections made by each executive officer for the year ended December 31, 2025.