Mark Kidd - 01 Mar 2026 Form 4 Insider Report for IRON MOUNTAIN INC (IRM)

Reporting relationship: EVP, GM Data Centers & ALM
Issuer ticker: IRM
Reported as of: 01 Mar 2026
Net transaction value: -$7,288,799
SEC form: 4
Accepted by SEC: 03 Mar 2026, 18:43:23 UTC
Prior SEC filing: 24 Feb 2026
Next SEC filing: 02 Apr 2026
Source filing: View source filing
Reporting owner signature: /s/ Christine Zhang, under Power of Attorney dated June 19, 2025, from Mark Kidd

Key filing fact

Mark Kidd filed Form 4 for IRON MOUNTAIN INC (IRM) on 03 Mar 2026.

Key facts

This page summarizes Mark Kidd's Form 4 filing for IRON MOUNTAIN INC (IRM).
4 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 03 Mar 2026, 18:43.

Change

Previous filing in this sequence was filed on 24 Feb 2026.
Current net transaction value: -$7,288,799.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001732058 Primary reporting owner

Kidd Mark

Relationship: EVP, GM Data Centers & ALM
Address: C/O IRON MOUNTAIN INCORPORATED, 85 NEW HAMPSHIRE AVENUE, SUITE 150, PORTSMOUTH
Signature: /s/ Christine Zhang, under Power of Attorney dated June 19, 2025, from Mark Kidd
Signature date: 03 Mar 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

IRM transaction

Common Stock, par value $.01 per share

Options Exercise

Transaction value: $0
Shares: +149,768
Change %: +305%
Price: $0.000000
Shares after: 198,849
Date: 01 Mar 2026
Ownership: Direct
Footnotes: F1

IRM transaction

Common Stock, par value $.01 per share

Tax liability

Transaction value: $6,645,179
Shares: -61,342
Change %: -31%
Price: $108.33
Shares after: 137,507
Date: 01 Mar 2026
Ownership: Direct
Footnotes: F2

IRM transaction

Common Stock, par value $.01 per share

Sale

Transaction value: $643,620
Shares: -6,000
Change %: -4.4%
Price: $107.27
Shares after: 131,507
Date: 02 Mar 2026
Ownership: Direct
Footnotes: F3

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

IRM transaction Derivative

Performance Units

Options Exercise

Transaction value: $0
Shares: -149,768
Change %: -100%
Price: $0.000000
Shares after: 0
Date: 01 Mar 2026
Ownership: Direct
Underlying class: Common Stock, par value $.01 per share
Underlying amount: 149,768
Exercise price
Footnotes: F4, F5

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Rule 10b5-1 trading plan

These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.

Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).

Explanation of responses 5 footnotes

Footnote 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.

Footnote 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.

Footnote F3

The transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 20, 2025.

Footnote F4

Each PU represents a contingent right to receive one share of Iron Mountain Incorporated common stock ("Common Stock").

Footnote 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.