IRON MOUNTAIN INC — Director's Dealing 2026

Mar 4, 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: IRON MOUNTAIN INC (IRM)
CIK: 0001020569
Period of Report: 2026-03-01

Reporting Person: Hytinen Barry (EVP and CFO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-03-01	Common Stock, par value $.01 per share	M	232977	—	Acquired	431495	Direct
2026-03-01	Common Stock, par value $.01 per share	F	104872	$108.33	Disposed	326623	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2026-03-01	Performance Units	$	M	232977	Disposed		Common Stock, par value $.01 per share (232977)	Direct

Footnotes

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 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.