[Form 3] American Tower Corporation Initial Statement of Beneficial Ownership

Rhea-AI Filing Summary

Reilly Eugene F filed an initial Form 3 reporting ownership of 135 shares of American Tower Corporation (AMT) common stock held directly. The filing notes a call option (obligation to sell) on 100 common shares exercisable 08/18/2025 and expiring 09/19/2025 with a $220 exercise price. The reporting person is identified as a Director and the triggering event date is 08/22/2025. The form was signed by an attorney-in-fact on 08/29/2025. The call option was entered into prior to the director appointment.

Positive

• Timely disclosure of initial beneficial ownership under Section 16
• Specific, clear details on share amounts and option terms (dates and strike)

Negative

• Small direct holding (135 shares) offers limited insight into reporting person's economic stake
• Call option is an obligation to sell, which could restrict potential upside for those 100 shares

Insights

Financial Analyst

TL;DR: Small direct holding and an existing call obligation create minimal market or valuation impact.

The filing discloses a direct stake of 135 shares and a pre-existing call option for 100 shares with a $220 strike and defined exercisable/expiration dates (08/18/2025–09/19/2025). These positions are modest in size relative to a large-cap REIT and therefore unlikely to influence AMT's market dynamics or signal significant insider buying or selling. Disclosure complies with Section 16 initial-reporting requirements.

Corporate Governance Expert

TL;DR: Timely Form 3 filing by a newly reported director shows procedural compliance; transaction history is limited.

The report identifies the reporting person as a Director and notes the call option predates board appointment, which is a relevant governance fact disclosed on the Form 3. The document provides clear, specific dates and amounts but no additional compensatory arrangements or related-party details. From a governance perspective, the filing fulfills transparency obligations but contains no material governance concerns based solely on the disclosed positions.

SEC Form 3

FORM 3

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

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

REILLY EUGENE F

(Last) (First) (Middle)

116 HUNTINGTON AVENUE

(Street)

BOSTON MA 02116

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
08/22/2025

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

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

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

5. 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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	135	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Call Option (Obligation to Sell)(1)	08/18/2025	09/19/2025	Common Stock	100	$220	D

Explanation of Responses:

1. The Call Option was entered into prior to the reporting person's appointment to the issuer's board of directors.

Remarks:

	/s/ Marina A. Breed, as attorney-in-fact	08/29/2025
	** 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 5 (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 did Reilly Eugene F report on Form 3 for AMT?

The filer reported 135 shares of AMT common stock held directly and a call option on 100 shares with a $220 exercise price.

When was the event triggering the Form 3 filing?

The Date of Event Requiring Statement is 08/22/2025.

What are the exercisable and expiration dates for the disclosed option?

The call option is listed as exercisable on 08/18/2025 and expiring on 09/19/2025.

How is the reporting person related to American Tower (AMT)?

The filing indicates the reporting person is a Director of American Tower Corporation.

Was the call option entered into before or after joining the board?

The filing states the call option was entered into prior to the reporting person's appointment to the issuer's board.