[Form 4] IRON MOUNTAIN INC Insider Trading Activity

Rhea-AI Filing Summary

Theodore R. Samuels II, a director of Iron Mountain Incorporated (IRM), reported purchases of phantom stock under the company’s directors deferred compensation plan on 10/03/2025. Two issuances of Phantom Stock were recorded: 76.052 phantom shares (reflecting dividend reinvestment) at a weighted-average underlying price of $104.422, and 331.138 phantom shares (reflecting quarterly cash compensation reinvested) at a weighted-average underlying price of $105.7. After these transactions the reported beneficial ownership totals were 10,192.552 and 10,523.69 common-stock-equivalent shares, respectively. The Phantom Shares will convert to common stock upon the reporting person’s disability or cessation of director service.

Positive

• Director compensation was deferred into Phantom Shares rather than immediate cash, aligning director pay with shareholder-equivalent exposure
• Phantom Shares are tied to common stock value, giving the director economic alignment without immediate dilution

Negative

• Phantom Shares will convert to common stock upon cessation or disability, which could increase outstanding shares if converted
• Weighted-average prices indicate multiple acquisition points, suggesting complexity in recordkeeping and potential variability in reported cost basis

Insights

Corporate Governance Analyst

Director received equity-equivalent compensation via phantom stock reinvestment.

The filings show the director elected to receive board compensation and dividend equivalents as Phantom Shares, which are payable in common stock upon disability or departure from the board. The transactions occurred on 10/03/2025

Key dependencies include the director’s continued service and the plan’s conversion conditions; investors can note the modest incremental dilution effect only if and when Phantom Shares convert to Common Stock within a material timeframe.

Compensation & Accounting Specialist

Phantom stock entries reflect non-cash board compensation and dividend reinvestment.

The two reported additions — 76.052 and 331.138 Phantom Shares — are recorded as equity equivalents with weighted-average underlying prices of $104.422 and $105.7, indicating multiple acquisition price points. These represent deferred, conditional compensation rather than immediate stock sales or open-market purchases.

Watch for vesting/settlement triggers tied to departure or disability that would convert these units into Common Stock and potentially affect outstanding share count when they become payable.

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
Estimated average burden
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^*

Samuels Theodore R. II

(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		76.052(2)		(1)	(1)	Common Stock	76.052	$104.422(3)	10,192.552	D
Phantom Stock	(1)	10/03/2025		A		331.138(4)		(1)	(1)	Common Stock	331.138	$105.7(5)	10,523.69	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 July 6, 2023 from Theodore R Samuels	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 Theodore R. Samuels II report on Form 4?

He reported acquiring Phantom Shares under the directors deferred compensation plan on 10/03/2025: 76.052 and 331.138 Phantom Shares, which are payable in common stock under plan terms.

What prices were reported for the Phantom Shares on the IRM Form 4?

The weighted-average underlying prices reported were $104.422 for the 76.052 shares and $105.7 for the 331.138 shares.

When will the Phantom Shares convert into IRM common stock?

The Phantom Shares will become payable in common stock following the reporting person’s disability or cessation of service as a director, per the filing.

How many common-stock-equivalent shares were reported after the transactions?

The filing shows beneficial ownership totals of 10,192.552 and 10,523.69 common-stock-equivalent shares following the reported transactions.

Do these transactions represent open-market purchases?

No. These are issuances of Phantom Shares under a deferred compensation plan, not open-market purchases of common stock.