Mark Kidd - 01 Mar 2026 Form 4 Insider Report for IRON MOUNTAIN INC (IRM)

Role: EVP, GM Data Centers & ALM
Signature: /s/ Christine Zhang, under Power of Attorney dated June 19, 2025, from Mark Kidd
Issuer symbol: IRM
Transactions as of: 01 Mar 2026
Net transactions value: -$7,288,799
Form type: 4
Filing time: 03 Mar 2026, 18:43:23 UTC
Previous filing: 24 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Kidd Mark	EVP, GM Data Centers & ALM	C/O IRON MOUNTAIN INCORPORATED, 85 NEW HAMPSHIRE AVENUE, SUITE 150, PORTSMOUTH	/s/ Christine Zhang, under Power of Attorney dated June 19, 2025, from Mark Kidd	03 Mar 2026	0001732058

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	IRM	Common Stock, par value $.01 per share	Options Exercise	$0	+149,768	+305%	$0.000000	198,849	01 Mar 2026	Direct	F1
transaction	IRM	Common Stock, par value $.01 per share	Tax liability	$6,645,179	-61,342	-31%	$108.33	137,507	01 Mar 2026	Direct	F2
transaction	IRM	Common Stock, par value $.01 per share	Sale	$643,620	-6,000	-4.4%	$107.27	131,507	02 Mar 2026	Direct	F3

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	IRM	Performance Units	Options Exercise	$0	-149,768	-100%	$0.000000	0	01 Mar 2026	Common Stock, par value $.01 per share	149,768		Direct	F4, F5

* 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	This acquisition is reported to reflect the full vesting of performance units ("PUs") previously granted to the Reporting Person on March 1, 2023. Effective February 16, 2026, the Compensation Committee of Iron Mountain Incorporated's Board of Directors determined the actual award of PUs under the grant after completion of the relevant performance period, and the PUs fully vested on March 1, 2026.
F2	Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding obligation in connection with the net settlement of the PUs and does not represent a sale.
F3	The transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 20, 2025.
F4	Each PU represents a contingent right to receive one share of Iron Mountain Incorporated common stock ("Common Stock").
F5	The PUs were initially granted to the Reporting Person on March 1, 2023. Effective as of February 16, 2026, the Compensation Committee determined the actual award of PUs under the grant after completion of the relevant performance period, and the PUs fully vested on March 1, 2026.