=== SEC Form 4 — Statement of Changes in Beneficial Ownership ===
Document Type: 4
Period of Report: 2026-03-01
10b5-1 Pre-arranged Plan: No
--- Issuer ---
Name: IRON MOUNTAIN INC (IRM)
CIK: 0001020569
--- Reporting Owner ---
Name: McIntosh Greg W
CIK: 0001769841
Role: Officer (EVP, Chief Commercial Officer)
--- Non-Derivative Transactions ---
[Transaction #1]
Security: Common Stock, par value $.01 per share
Date: 2026-03-01 | Code: M (Exercise of derivative)
Shares: +123,144 | Price: $0.00
Shares Owned After: 141,251 | Ownership: D (Direct)
Footnotes:
[F1] 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.
[Transaction #2]
Security: Common Stock, par value $.01 per share
Date: 2026-03-01 | Code: F (Payment of exercise/tax)
Shares: -55,617 | Price: $108.33
Total Value: $6,024,989.61
Shares Owned After: 85,634 | Ownership: D (Direct)
Footnotes:
[F2] 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.
--- Derivative Transactions ---
[Transaction #1]
Security: Performance Units
Date: 2026-03-01 | Code: M (Exercise of derivative)
Shares: -123,144 | Price: $0.00
Shares Owned After: 0 | Ownership: D (Direct)
Footnotes:
[F3] Each PU represents a contingent right to receive one share of Iron Mountain Incorporated common stock ("Common Stock").
[F4] 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.
[F4] 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.
--- Footnotes (Complete Index) ---
F1: 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.
F2: 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.
F3: Each PU represents a contingent right to receive one share of Iron Mountain Incorporated common stock ("Common Stock").
F4: 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.
--- Signature ---
/s/ /s/ Christine Zhang, under Power of Attorney dated June 19, 2025, from Greg McIntosh (2026-03-03)
