X0508 4 2026-02-16 0 0001020569 IRON MOUNTAIN INC IRM 0002045996 Bhargava Mithu C/O IRON MOUNTAIN INCORPORATED 85 NEW HAMPSHIRE AVE, SUITE 150 PORTSMOUTH NH 03801 0 1 0 0 EVP, GM Digital Business Unit 0 Performance Units 2026-02-16 4 A 0 37085 0 A Common Stock, par value $.01 per share 37085 51919 D Performance Units 2026-02-16 4 A 0 43652 0 A Common Stock, par value $.01 per share 43652 61113 D Each Performance Unit ("PU") represents a contingent right to receive one share of Iron Mountain Incorporated common stock ("Common Stock"). The PUs were initially granted to the Reporting Person on March 1, 2023. This Form 4 is being filed to reflect the determination by the Compensation Committee, effective as of February 16, 2026, of the actual award of PUs under the grant after completion of the relevant performance period. The PU were initially granted to the Reporting Person on March 1, 2023, and will fully vest on March 1, 2026. The PUs were initially granted to the Reporting Person on July 3, 2023. This Form 4 is being filed to reflect the determination by the Compensation Committee, effective as of February 16, 2026, of the actual award of PUs under the grant after completion of the relevant performance period. The PU were initially granted to the Reporting Person on July 3, 2023, and will fully vest on March 1, 2026. /s/ Christine Zhang, under Power of Attorney dated November 19, 2024, from Mithu Bhargava 2026-02-18