Iron Mountain (IRM) 4: Simons Doyle bought 1,892 shares of Common Stock, par value… (May 11, 2026)

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-05-07 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: IRON MOUNTAIN INC (IRM) CIK: 0001020569 --- Reporting Owner --- Name: Simons Doyle CIK: 0001185922 Role: Director --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock, par value $.01 per share Date: 2026-05-07 | Code: A (Grant or award) Shares: +1,892 | Price: $0.00 Shares Owned After: 1,892 | Ownership: D (Direct) Footnotes: [F1] Consists of shares issuable upon the settlement of restricted stock units ("RSUs") granted on May 7, 2026. The RSUs vest in their entirety on the grant date. --- Holdings --- [Holding #1] Security: Phantom Stock Ownership: D (Direct) Footnotes: [F2] 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. [F2] 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. [F2] 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. --- Footnotes (Complete Index) --- F1: Consists of shares issuable upon the settlement of restricted stock units ("RSUs") granted on May 7, 2026. The RSUs vest in their entirety on the grant date. F2: 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. --- Signature --- /s/ /s/ Keely Stewart, under Power of Attorney dated April 17, 2023 from Doyle R. Simons (2026-05-11)