Iron Mountain (NYSE: IRM) CFO vests shares and withholds stock for taxes

Rhea-AI Filing Summary

Iron Mountain EVP and CFO Barry Hytinen reported the vesting and net settlement of performance units into common stock. On March 1, 2026, 232,977 performance units granted on March 1, 2023 were fully vested and converted into the same number of Iron Mountain common shares, following the Compensation Committee’s award determination on February 16, 2026.

To cover income tax withholding on this vesting, 104,872 common shares were withheld by Iron Mountain at $108.33 per share, which the company notes does not represent a sale. After these transactions, Hytinen directly owned 326,623 shares of Iron Mountain common stock.

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

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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^*

Hytinen Barry

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
03/01/2026

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
Common Stock, par value $.01 per share	03/01/2026		M		232,977(1)	A	$0	431,495	D
Common Stock, par value $.01 per share	03/01/2026		F		104,872(2)	D	$108.33	326,623	D

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
Performance Units	(3)	03/01/2026		M			232,977	(4)	(4)	Common Stock, par value $.01 per share	232,977	$0	0	D

Explanation of Responses:

1. 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.

2. 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.

3. Each PU represents a contingent right to receive one share of Common Stock.

4. 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.

Remarks:

	Barry A. Hytinen	03/03/2026
	** Signature of Reporting Person	Date
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