Theodore R. Samuels II - 29 May 2025 Form 4 Insider Report for IRON MOUNTAIN INC (IRM)

Role: Director
Signature: /s/ Keely Stewart, under Power of Attorney dated July 6, 2023 from Theodore R Samuels
Issuer symbol: IRM
Transactions as of: 29 May 2025
Net transactions value: $0
Form type: 4
Filing time: 02 Jun 2025, 16:28:00 UTC
Previous filing: 14 May 2025
Next filing: 01 Jul 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Samuels Theodore R. II	Director	C/O IRON MOUNTAIN INCORPORATED, 85 NEW HAMPSHIRE AVENUE, SUITE 150, PORTSMOUTH	/s/ Keely Stewart, under Power of Attorney dated July 6, 2023 from Theodore R Samuels	02 Jun 2025	0001688276

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	Phantom Stock	Award	$0	+2,249	+30%	$0.000000	9,693	29 May 2025	Common Stock	2,249		Direct	F1, F2

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

Explanation of Responses:

Id	Content
F1	Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan (the "DDCP"), the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.
F2	Consists of shares issuable upon the settlement of restricted stock units ("RSUs") granted on May 29, 2025. The RSUs vest in their entirety on the grant date. The Reporting Person has elected that upon vesting of RSUs, receipt of the shares of Common Stock be deferred under the DDCP; accordingly, upon vesting, the Reporting Person will instead receive an equal number of Phantom Shares.

Content

Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan (the "DDCP"), the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

Consists of shares issuable upon the settlement of restricted stock units ("RSUs") granted on May 29, 2025. The RSUs vest in their entirety on the grant date. The Reporting Person has elected that upon vesting of RSUs, receipt of the shares of Common Stock be deferred under the DDCP; accordingly, upon vesting, the Reporting Person will instead receive an equal number of Phantom Shares.