[Form 4] IRON MOUNTAIN INC Insider Trading Activity

Rhea-AI Filing Summary

Iron Mountain director reported acquisition of phantom stock tied to director compensation and deferred plan. The Form 4 shows that Doyle R. Simons, a director, acquired 333.553 Phantom Shares on 10/03/2025 at a weighted average equivalent price of $104.422 and an additional 331.138 Phantom Shares on 10/03/2025 at a weighted average equivalent price of $105.7. Each Phantom Share is the economic equivalent of one share of common stock and will be payable in shares upon the reporting person’s disability or cessation of director service under the Directors Deferred Compensation Plan. After these entries the filing shows beneficial ownership figures of 44,703.315 and 45,034.453 common shares following the respective transactions. The Form 4 was signed under power of attorney on 10/07/2025.

Positive

• Participation in Directors Deferred Compensation Plan aligns director compensation with shareholder value via phantom shares
• Dividend-equivalent reinvestment applied to 333.553 Phantom Shares increases long-term equity linkage
• Record of additional phantom units (331.138) from quarterly cash compensation shows consistent equity-based pay

Negative

• None.

Insights

Corporate Governance Analyst

TL;DR: Director used deferred-compensation mechanisms to receive phantom shares that convert to common stock on service termination.

The transaction reflects participation in the Directors Deferred Compensation Plan, where phantom shares mirror the economic exposure of common stock and include dividend-equivalent reinvestment. This structure preserves cash flow for the company while granting equity-linked value to the director.

Risks and dependencies include the conversion trigger tied to disability or cessation of service and the mechanics of dividend-equivalent accrual. Investors can track actual share issuance only when phantom shares become payable; until then, these are contingent economic interests recorded as phantom units.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a 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). See Instruction 10.

1. Name and Address of Reporting Person^*

Simons Doyle

(Last) (First) (Middle)

C/O IRON MOUNTAIN INCORPORATED

85 NEW HAMPSHIRE AVENUE, SUITE 150

(Street)

PORTSMOUTH NH 03801

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
IRON MOUNTAIN INC [ IRM ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
10/03/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Phantom Stock	(1)	10/03/2025		A		333.553(2)		(1)	(1)	Common Stock	333.553	$104.422(3)	44,703.315	D
Phantom Stock	(1)	10/03/2025		A		331.138(4)		(1)	(1)	Common Stock	331.138	$105.7(5)	45,034.453	D

Explanation of Responses:

1. Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, 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.

2. These shares give effect to dividends paid on Common Stock as if reinvested in Phantom Shares.

3. The price reported in Column 8 is a weighted average price. These shares of Common Stock were acquired in multiple transactions at prices ranging from $104.349 to $104.524, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock acquired at each separate price within the ranges set forth in this footnote (3).

4. These shares give effect to the Reporting Person's quarterly cash compensation for services on the board of directors of the Company as if reinvested in Phantom Shares.

5. The price reported in Column 8 is a weighted average price. These shares of Common Stock were acquired in multiple transactions at prices ranging from $105.569 to $105.819, inclusive. The Reporting Person undertakes to provide the Company, any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock acquired at each separate price within the ranges set forth in this footnote (5).

Remarks:

	/s/ Keely Stewart, under Power of Attorney dated April 17, 2023 from Doyle R. Simons	10/07/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did IRM director Doyle R. Simons report on Form 4?

The filing reports acquisition of 333.553 and 331.138 Phantom Shares on 10/03/2025, convertible to common stock upon disability or cessation of director service.

How many common-stock equivalents were reported after the transactions for IRM?

The Form 4 shows beneficial ownership figures of 44,703.315 and 45,034.453 common shares following the respective reported transactions.

What prices were used for the phantom-share entries?

The weighted average equivalent prices reported are $104.422 for the 333.553 units and $105.7 for the 331.138 units.

When will the phantom shares convert into actual common stock?

Per the filing, phantom shares become payable in common stock following the reporting person’s disability or cessation of service as a director under the Directors Deferred Compensation Plan.

Who signed the Form 4 for Doyle R. Simons?

The Form 4 was signed under power of attorney by Keely Stewart on 10/07/2025.