Kidd Mark 4

4 · IRON MOUNTAIN INC · Filed Mar 3, 2026

Form 4

Period: 2026-03-01

EVP, GM Data Centers & ALM

Transactions

Exercise/Conversion
Common Stock, par value $.01 per share
[F1]
2026-03-01+149,768→ 198,849 total
Tax Payment
Common Stock, par value $.01 per share
[F2]
2026-03-01$108.33/sh−61,342$6,645,179→ 137,507 total
Sale
Common Stock, par value $.01 per share
[F3]
2026-03-02$107.27/sh−6,000$643,620→ 131,507 total
Exercise/Conversion
Performance Units
[F4][F5]
2026-03-01−149,768→ 0 total
→ Common Stock, par value $.01 per share (149,768 underlying)

Footnotes (5)

[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]The transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 20, 2025.
[F4]Each PU represents a contingent right to receive one share of Iron Mountain Incorporated common stock ("Common Stock").
[F5]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/ Christine Zhang, under Power of Attorney dated June 19, 2025, from Mark Kidd|2026-03-03

Documents

3 files