Iron Mountain Inc
IRM- Exchange
- NYSE
- Industry
- Real Estate Investment Trusts
- SEC CIK
- 0001020569
In the last 90 days, Iron Mountain Inc insiders filed 0 open-market purchases and 8 sales; 1,173 institutions reported holding it in 13F filings for Q2 2026, worth $32.4B in total; no superinvestor holds it.
Holders of 5% or more of IRM
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Iron Mountain Inc, largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| Cohen & Steers, Inc. | 13G | 5.43%16.0M shares | +1.08 ppfrom 4.35% | Mar 7, 20252 filings | Nov 14, 2025 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
2 Schedule 13D and 13G filings on Iron Mountain Inc, newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Nov 14, 20256:40 AM ET | Cohen & Steers, Inc.and 4 others | 13G | 5.43%16.0M shares | +1.08 ppfrom 4.35% | Sep 30, 2025 | SEC |
| Mar 7, 20259:16 AM ET | Cohen & Steers, Inc.and 4 others | 13G/A | 4.35%12.8M shares | –Below 5% | Feb 28, 2025 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Iron Mountain Inc shares.
No Form 144 notices for Iron Mountain Inc are on file.