[Form 4] AMERICAN TOWER CORP /MA/ Insider Trading Activity

Rhea-AI Filing Summary

Eugene F. Reilly, a director of American Tower Corp (AMT), reported transactions dated 09/19/2025. He disposed of 135 shares of AMT common stock. The filing also reports a derivative transaction: a call option (obligation to sell) with $220 strike showing a related disposition of 100 underlying shares and 0 shares held thereafter. The form is signed by an attorney-in-fact on 09/23/2025.

Insights

Financial Analyst

TL;DR: Routine insider dispositions recorded: small direct sale and a derivative-related disposition, with no remaining underlying shares reported.

The report shows a direct disposition of 135 shares and a derivative transaction involving a call option tied to 100 underlying shares with a $220 strike, resulting in zero shares held from that derivative. The sizes reported are explicit and limited to the amounts listed; the filing does not provide context on proceeds, reasons, or standing ownership beyond post-transaction counts. Based solely on the disclosed numbers, this appears to be a routine schedule of insider activity.

Corporate Governance Expert

TL;DR: Disclosure complies with Section 16 reporting: director reported both non-derivative and derivative dispositions promptly.

The form identifies the reporting person as a director and indicates the form was filed by one reporting person. Transactions are dated 09/19/2025 and the signature block shows filing via attorney-in-fact on 09/23/2025. The document contains no governance concerns, executive titles, or explanatory remarks beyond the transaction entries; it is a straightforward Section 16 change-in-beneficial-ownership filing.

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

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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^*

REILLY EUGENE F

(Last) (First) (Middle)

116 HUNTINGTON AVENUE

(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
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/19/2025

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								135	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
Call Option (Obligation to Sell)	$220	09/19/2025		E			1	08/18/2025	09/19/2025	Common Stock	100	$0	0	D

Explanation of Responses:

Remarks:

	/s/ Marina A. Breed, as attorney-in-fact	09/23/2025
	** 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 transactions did AMT director Eugene Reilly report on Form 4?

He reported a direct disposition of 135 shares of AMT common stock and a derivative-related disposition tied to 100 underlying shares.

When were the transactions dated in the AMT Form 4 filed by Eugene Reilly?

The transactions are dated 09/19/2025 and the form bears a signature dated 09/23/2025 by an attorney-in-fact.

What derivative instrument is disclosed on the AMT Form 4 for Eugene Reilly?

A call option (obligation to sell) with a $220 strike is reported, linked to 100 shares of common stock and showing 0 shares held thereafter.

What is Eugene Reilly's relationship to AMT as stated on the Form 4?

The form lists him as a Director of American Tower Corp and the filing was made by one reporting person.

Does the Form 4 include reasons for the transactions or proceeds received?

No. The filing lists the transactions, amounts, dates, and post-transaction holdings but provides no explanation of reasons or proceeds.