Greg W. McIntosh - 01 Mar 2026 Form 4 Insider Report for IRON MOUNTAIN INC (IRM)

Role: EVP, Chief Commercial Officer
Signature: /s/ Christine Zhang, under Power of Attorney dated June 19, 2025, from Greg McIntosh
Issuer symbol: IRM
Transactions as of: 01 Mar 2026
Net transactions value: -$6,024,990
Form type: 4
Filing time: 03 Mar 2026, 18:36:52 UTC
Previous filing: 18 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
McIntosh Greg W	EVP, Chief Commercial Officer	C/O IRON MOUNTAIN INCORPORATED, 85 NEW HAMPSHIRE AVENUE, SUITE 150, PORTSMOUTH	/s/ Christine Zhang, under Power of Attorney dated June 19, 2025, from Greg McIntosh	03 Mar 2026	0001769841

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	+123,144	+680%	$0.000000	141,251	01 Mar 2026	Direct	F1
transaction	IRM	Common Stock, par value $.01 per share	Tax liability	$6,024,990	-55,617	-39%	$108.33	85,634	01 Mar 2026	Direct	F2

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	-123,144	-100%	$0.000000	0	01 Mar 2026	Common Stock, par value $.01 per share	123,144		Direct	F3, F4

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

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	Each PU represents a contingent right to receive one share of Iron Mountain Incorporated common stock ("Common Stock").
F4	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.