Iron Mountain Incorporated (IRM) Shareholders & Insider Trades
Iron Mountain shareholders at a glance
The largest holder of Iron Mountain stock is BlackRock Advisors LLC, with 26.1 million shares (8.77% of the company), worth about $3.01 billion as of September 25, 2026. The 10 largest holders together own 44.6%.
In Q2 2026, 1,219 institutional holdings reports listed 312.0 million shares worth $32.90 billion, up 23.3% in shares from Q1 2026.
Insiders reported 93 transactions in the last two years: 40 sales worth $180.34 million and 1 purchase. The newest one on file is from May 12, 2026 (Arway Pamela M., Director).
Major holders as of September 25, 2026; quarterly totals from institutional holdings reports (latest Q2 2026); insider transactions on file through May 12, 2026.
Iron Mountain Incorporated
Shareholders Summary
2026Q2
Ownership by Type
Geographic Distribution
Largest Iron Mountain shareholders
| Holder | Shares | % of company | Value |
|---|---|---|---|
| BlackRock Advisors LLC | 26.1 million | 8.77% | $3.0B |
| Vanguard Portfolio Management LLC | 25.6 million | 8.59% | $2.9B |
| Vanguard Capital Management LLC | 19.0 million | 6.37% | $2.2B |
| State Street Corporation | 17.6 million | 5.92% | $2.0B |
| Cohen & Steers Capital Management, Inc. | 12.0 million | 4.04% | $1.4B |
| Geode Capital Management LLC | 8.6 million | 2.90% | $998.0M |
| Fidelity Management & Research Co. LLC | 7.9 million | 2.64% | $908.0M |
| BlackRock Life Ltd. | 6.9 million | 2.31% | $792.0M |
| DFA Australia Ltd. | 4.5 million | 1.53% | $524.0M |
| Eaton Vance Management | 4.4 million | 1.49% | $511.0M |
As of September 25, 2026.
Iron Mountain institutional holdings by quarter
| Quarter | Reports | Shares | Value |
|---|---|---|---|
| Q2 2026 | 1,219 | 312.0 million | $32.9B |
| Q1 2026 | 1,129 | 253.0 million | $25.8B |
| Q4 2025 | 1,059 | 259.0 million | $21.5B |
| Q3 2025 | 1,069 | 253.0 million | $25.8B |
| Q2 2025 | 1,098 | 252.0 million | $25.9B |
| Q1 2025 | 1,044 | 246.0 million | $21.1B |
| Q4 2024 | 1,123 | 238.0 million | $25.0B |
| Q3 2024 | 1,114 | 246.0 million | $29.1B |
Shares and value held by institutions that file quarterly holdings reports (options not included).
Iron Mountain insider trades
| Insider | Date | Title | Transaction | Value |
|---|---|---|---|---|
| Arway Pamela M. | May 12, 2026 | Director | Sale at price 128.97 per share. | $244,011 |
| Meaney William L | May 8, 2026 | Chief Executive Officer | Sale at price 128.52 - 129.19 per share. | $5.0M |
| Kidd Mark | May 8, 2026 | Officer | Sale at price 127.91 per share. | $767,460 |
| Meaney William L | May 8, 2026 | Chief Executive Officer | Conversion of Exercise of derivative security at price 37.00 per share. | $1.4M |
| Felix June Yee | May 7, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Allerton Jennifer | May 7, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Matlock Robin | May 7, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Simons Doyle R | May 7, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Kelly Christie Barton | May 7, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Arway Pamela M. | May 7, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Rakowich Walter C. | May 7, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Ford Monte E. | May 7, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
Newest 12 of 93 insider transactions in the last two years.
Questions and answers
Who owns the most Iron Mountain stock?
BlackRock Advisors LLC, with 8.77% of the company (as of September 25, 2026). Next: Vanguard Portfolio Management LLC (8.59%) and Vanguard Capital Management LLC (6.37%).
How many institutions own Iron Mountain stock?
1,219 institutional holdings reports listed Iron Mountain shares in Q2 2026, 312.0 million shares in all worth $32.90 billion.
Are Iron Mountain insiders buying or selling the stock?
In the last two years insiders reported 40 sales and 1 purchase (93 transactions in all); the newest on file is from May 12, 2026.
