American Tower (AMT) CEO reports RSU grant and tax-withholding share dispositions

Rhea-AI Filing Summary

American Tower President and CEO Steven O. Vondran reported routine equity compensation and related tax withholding transactions in Common Stock. On March 10, 2026, he acquired 20,955 shares through a grant of restricted stock units under the company’s 2007 Equity Incentive Plan; these RSUs vest in thirds annually over three years, starting one year from the grant date.

To cover withholding taxes on the vesting of previously granted RSUs and performance-based restricted stock units, shares were delivered back to the issuer: 15,269 shares on March 10, 2026 at $186.12 per share and 2,158 shares on March 11, 2026 at $182.85 per share. These are tax-withholding dispositions, not open-market sales. After these transactions, Vondran directly held 108,902 shares of Common Stock.

Insider Trade Summary

3 transactions reported

Mixed 3 txns

Insider Vondran Steven O

Role President and CEO

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	2,158	$182.85	$395K
Grant/Award	Common Stock	20,955	$0.00	--
Tax Withholding	Common Stock	15,269	$186.12	$2.84M

Holdings After Transaction: Common Stock — 108,902 shares (Direct)

Footnotes (1)

1. 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. Shares delivered to the issuer for the payment of withholding taxes in connection with the vesting of RSUs and performance-based restricted stock units previously granted under the Plan. Shares delivered to the issuer for the payment of withholding taxes in connection with the vesting of RSUs previously granted under the Plan.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Vondran Steven O

(Last) (First) (Middle)

222 BERKELEY STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
AMERICAN TOWER CORP /MA/ [ AMT ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President and CEO

3. Date of Earliest Transaction (Month/Day/Year)
03/10/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/10/2026		A		20,955(1)	A	$0	126,329	D
Common Stock	03/10/2026		F(2)		15,269	D	$186.12	111,060	D
Common Stock	03/11/2026		F(3)		2,158	D	$182.85	108,902	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. 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.

2. Shares delivered to the issuer for the payment of withholding taxes in connection with the vesting of RSUs and performance-based restricted stock units previously granted under the Plan.

3. Shares delivered to the issuer for the payment of withholding taxes in connection with the vesting of RSUs previously granted under the Plan.

Remarks:

	/s/ Marina A. Breed, as attorney-in-fact	03/12/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transactions did AMT CEO Steven O. Vondran report on this Form 4?

Steven O. Vondran reported a grant of 20,955 shares of Common Stock via restricted stock units and two tax-withholding dispositions totaling 17,427 shares. These events reflect routine equity compensation and related tax obligations rather than open-market buying or selling of AMT shares.

How many AMT shares did CEO Steven O. Vondran acquire through grants in this filing?

He acquired 20,955 shares of AMT Common Stock through a grant of restricted stock units. The RSUs were issued under the 2007 Equity Incentive Plan and vest in three equal annual installments, beginning one year from the grant date, subject to the plan’s standard conditions.

Were any of Steven O. Vondran’s AMT share transactions open-market sales or purchases?

No. The Form 4 shows a grant of restricted stock units and tax-withholding dispositions only. Shares were delivered to American Tower to pay withholding taxes on vesting RSUs and performance-based restricted stock units, rather than being sold or bought in open-market transactions.

How many AMT shares were withheld for taxes from Steven O. Vondran’s equity awards?

A total of 17,427 shares were withheld for taxes: 15,269 shares at $186.12 per share on March 10, 2026, and 2,158 shares at $182.85 per share on March 11, 2026. These shares were delivered back to the issuer to satisfy withholding obligations.

What is Steven O. Vondran’s AMT shareholding after the reported transactions?

Following the reported grant and tax-withholding dispositions, Steven O. Vondran directly holds 108,902 shares of American Tower Common Stock. This figure represents his direct ownership position as shown in the Form 4 after the March 11, 2026 transaction recorded in the filing.

How do the reported AMT RSUs for Steven O. Vondran vest over time?

The 20,955 restricted stock units granted to Steven O. Vondran vest in three equal annual installments. Vesting begins one year from the grant date, with one-third of the RSUs vesting each year over a three-year period, assuming continued satisfaction of plan terms.