(AMT)

Role: EVP & Chief Operating Officer
Signature: /s/ Marina A. Breed, as attorney-in-fact
Issuer symbol: AMT
Transactions as of: 02 Mar 2026
Net transactions value: -$7,872,920
Form type: 4
Filing time: 04 Mar 2026, 16:20:39 UTC
Previous filing: 12 Mar 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Noel Eugene M	EVP & Chief Operating Officer	222 BERKELEY STREET, BOSTON	/s/ Marina A. Breed, as attorney-in-fact	04 Mar 2026	0002000070

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	AMT	Common Stock	Options Exercise		+41,209	+139%	$94.71^*	70,801	02 Mar 2026	Direct	F1
transaction	AMT	Common Stock	Sale	$992,625	-5,242	-7.4%	$189.36	65,559	02 Mar 2026	Direct	F2, F3
transaction	AMT	Common Stock	Sale	$1,403,960	-7,378	-11%	$190.29	58,181	02 Mar 2026	Direct	F2, F4
transaction	AMT	Common Stock	Sale	$4,135,006	-21,604	-37%	$191.40	36,577	02 Mar 2026	Direct	F2, F5
transaction	AMT	Common Stock	Sale	$1,341,330	-6,985	-19%	$192.03	29,592	02 Mar 2026	Direct	F2, F6

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	AMT	Option to Purchase Common Stock	Options Exercise		-41,209	-100%	$0.000000^*	0	02 Mar 2026	Common Stock	41,209	$94.71	Direct	F7

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

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).

Explanation of Responses:

Id	Content
F1	Includes 73 and 46 shares acquired under the issuer's employee stock purchase plan in May 2025 and November 2025, respectively.
F2	The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 26, 2025.
F3	Represents the weighted average price of shares sold in multiple same-day transactions at prices ranging from $188.82 to $189.78 per share.
F4	Represents the weighted average price of shares sold in multiple same-day transactions at prices ranging from $189.92 to $190.88 per share.
F5	Represents the weighted average price of shares sold in multiple same-day transactions at prices ranging from $190.92 to $191.91 per share.
F6	Represents the weighted average price of shares sold in multiple same-day transactions at prices ranging from $191.92 to $192.19 per share.
F7	This option was granted pursuant to the 2007 Equity Incentive Plan, as amended, and is exercisable in 25% cumulative annual increments beginning March 10, 2017.