Iron Mountain (IRM) insider details RSU vesting and 469-share tax sale

Rhea-AI Filing Summary

Iron Mountain Incorporated executive reports RSU vesting and tax share withholding. The company’s EVP, General Counsel and Secretary reported the partial vesting of restricted stock units previously granted on January 2, 2024. On January 2, 2026, 1,214 shares of common stock were acquired at an exercise price of $0 upon conversion of RSUs. On the same date, 469 shares of common stock were disposed of at $83.24 per share, described as a transaction with code “F,” which typically reflects shares withheld to cover taxes.

Following these transactions, the executive beneficially owns 5,752 shares of Iron Mountain common stock directly, along with 1,214 RSUs. The RSU award originally covered 3,642 shares of common stock and vests in three substantially equal annual installments beginning on the first anniversary of the January 2, 2024 grant date.

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^*

Altamura Michelle Vervais

(Last) (First) (Middle)

C/O IRON MOUNTAIN INCORPORATED

85 NEW HAMPSHIRE AVE, 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, General Counsel, Sec.

3. Date of Earliest Transaction (Month/Day/Year)
01/02/2026

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	01/02/2026		M		1,214(1)	A	$0	6,221	D
Common Stock, par value $.01 per share	01/02/2026		F		469	D	$83.24	5,752	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
Restricted Stock Units	(2)	01/02/2026		M			1,214	(3)	(3)	Common Stock, par value $.01 per share	1,214	$0	1,214	D

Explanation of Responses:

1. This acquisition is reported to reflect the partial vesting of restricted stock units ("RSUs") previously granted to the Reporting Person on January 2, 2024.

2. Each RSU represents a contingent right to receive one share of Common Stock.

3. The RSUs, representing a contingent right to receive a total of 3,642 shares of Common Stock, were granted to the Reporting Person on January 2, 2024 and vest in three substantially equal annual installments beginning on the first anniversary of the grant date.

Remarks:

	/s/ Christine Zhang, under Power of Attorney dated September 17, 2024, from Michelle Altamura	01/06/2026
	** 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 insider transaction did IRM report for its EVP, General Counsel and Secretary?

The executive reported the partial vesting of previously granted restricted stock units, resulting in the acquisition of 1,214 shares of Iron Mountain common stock on January 2, 2026, and the disposal of 469 shares in a transaction coded “F.”

How many Iron Mountain (IRM) shares does the executive own after this Form 4 transaction?

After the reported transactions, the executive beneficially owns 5,752 shares of Iron Mountain common stock directly, plus 1,214 restricted stock units representing a contingent right to receive an equal number of shares.

What does the 469-share transaction at $83.24 mean for IRM’s insider filing?

The Form 4 shows the disposition of 469 shares of Iron Mountain common stock at $83.24 per share with transaction code “F,” which in this context reflects shares withheld in connection with the RSU vesting, commonly to satisfy tax obligations.

What are the terms of the RSU grant reported by the IRM executive?

The executive’s RSU award covers a total of 3,642 restricted stock units, each representing a contingent right to receive one share of Iron Mountain common stock. The RSUs were granted on January 2, 2024 and vest in three substantially equal annual installments beginning on the first anniversary of the grant date.

How many RSUs remain outstanding for the IRM executive after this vesting event?

Table II shows that after the January 2, 2026 transaction the executive beneficially owns 1,214 restricted stock units, each linked to one share of Iron Mountain common stock.

Is this IRM insider transaction a joint filing by multiple reporting persons?

No. The form indicates it is a Form filed by one reporting person, covering the holdings and transactions of a single Iron Mountain executive.