Iron MountainIRM
13F holders, Q1 2026 (March 31)1,090holders +79
158new positions
91sold out
10famous investors
$102.07avg. 13F price*
At the end of Q1 2026, 1,090 institutions reported holding Iron Mountain Inc. (IRM) in their 13F filings, up 79 from Q4 2025. 158 opened new positions and 91 sold out. The largest holders were BlackRock, Inc. ($3.4B), Vanguard Portfolio Management LLC ($2.6B) and Vanguard Capital Management LLC ($1.9B). 10 famous investors held it, including Ron Baron (0.2% of Baron Capital (BAMCO)'s portfolio), Cliff Asness (0.1% of AQR Capital Management's portfolio) and Steve Cohen (0.1% of Point72 Asset Management's portfolio).
- Company
- Iron Mountain Inc.
- Filed as
- IRON MTN INC DEL (Q1 2026)
- Sector
- Real Estate
- CUSIP
- 46284V101
- Latest filing quarter
- Q2 2026
History
Number of 13F holders
Total Exit/New Position Q4 2025 → Q1 2026
| Institutions | Total Value | |
|---|---|---|
| New Positions | 158 | $389.1M |
| Exits | 91 | $94.9M |
All 13F filers, Q4 2025 → Q1 2026: 15,093,532 shares bought and 14,861,424 shares sold, net +232,108 shares. Counts holders who added, trimmed, opened or closed a position; split-adjusted.
Ownership 1,090 holders
| BlackRock, Inc. | 0.06% | Add +0.3% | 33,021,354 | $3.4B |
| Vanguard Portfolio Management LLC | 0.13% | — | 25,015,557 | $2.6B |
| Vanguard Capital Management LLC | 0.05% | — | 18,758,889 | $1.9B |
| State Street Corp. | 0.06% | Add +3.9% | 17,551,633 | $1.8B |
| Cohen & Steers, Inc. | 2.87% | Reduce -14.5% | 16,169,341 | $1.7B |
| Geode Capital Management, LLC | 0.05% | Add +2.3% | 8,486,127 | $863.7M |
| FMR LLC | 0.04% | Reduce -6.3% | 7,484,398 | $764.5M |
| Morgan Stanley | 0.03% | Add +29.3% | 4,652,247 | $475.2M |
| Principal Financial Group Inc. | 0.25% | Add +8.5% | 4,566,093 | $466.4M |
| Dimensional Fund Advisors LP | 0.10% | Add +2.8% | 4,552,286 | $464.9M |
| Northern Trust Corp. | 0.06% | Reduce -0.1% | 4,150,486 | $423.9M |
| Charles Schwab Investment Management Inc. | 0.06% | Add +3.4% | 4,013,007 | $409.9M |
| Invesco Ltd. | 0.04% | Reduce -11.2% | 3,921,521 | $400.5M |
| Legal & General Group Plc | 0.07% | Reduce -6.6% | 3,135,074 | $320.2M |
| Daiwa Securities Group Inc. | 0.92% | Reduce -15.0% | 3,107,440 | $317.4M |
| Deutsche Bank AG | 0.10% | Add +21.6% | 3,092,084 | $315.8M |
| Prudential Financial Inc. | 0.30% | Add +4.6% | 2,416,063 | $246.8M |
| Centersquare Investment Management LLC | 2.44% | Reduce -12.2% | 2,310,045 | $235.9M |
| Goldman Sachs Group Inc. | 0.03% | Add +45.3% | 2,216,672 | $226.4M |
| Vontobel Holding Ltd. | 0.74% | Add +25.3% | 2,116,877 | $216.2M |
| Nuveen, LLC | 0.06% | Reduce -2.8% | 2,068,408 | $211.3M |
| JPMorgan Chase & Co. | 0.01% | Add +10.1% | 2,123,358 | $207.2M |
| Capital World Investors | 0.03% | Reduce -11.8% | 1,867,169 | $190.7M |
| Ameriprise Financial Inc. | 0.04% | Add +6.1% | 1,851,007 | $189.1M |
| AQR Capital Management | 0.08% | Add +100.0% | 1,846,073 | $183.1M |
| Vanguard Fiduciary Trust Co. | 0.04% | — | 1,652,888 | $168.8M |
| Bank of New York Mellon Corp | 0.03% | Reduce -3.6% | 1,624,836 | $166.0M |
| Duff & Phelps Investment Management Co. | 1.67% | Reduce -0.3% | 1,575,337 | $160.9M |
| Russell Investments Group, Ltd. | 0.16% | Add +3.5% | 1,455,113 | $148.4M |
| Contour Asset Management LLC | 4.80% | Reduce -49.0% | 1,444,823 | $147.6M |
| Royal Bank of Canada | 0.03% | Add +9.7% | 1,410,720 | $144.1M |
| Bank of America Corp. | 0.01% | Reduce -7.3% | 1,399,375 | $142.9M |
| PGGM Investments | 2.45% | Reduce -17.3% | 1,369,998 | $139.9M |
| HSBC Holdings PLC | 0.08% | Add +20.6% | 1,272,855 | $130.0M |
| CBRE Investment Management Listed Real Assets LLC | 1.88% | Reduce -14.4% | 1,237,915 | $126.4M |
| DekaBank Deutsche Girozentrale | 0.19% | No change | 1,122,500 | $116.6M |
| Amundi | 0.03% | Reduce -18.1% | 1,091,574 | $111.5M |
| Sei Investments Co. | 0.09% | Reduce -4.9% | 974,792 | $99.6M |
| Sumitomo Mitsui Trust Group, Inc. | 0.06% | Add +3.0% | 933,722 | $95.4M |
| Mitsubishi UFJ Asset Management Co., Ltd. | 0.06% | Add +8.2% | 908,365 | $92.8M |
| Swiss National Bank | 0.05% | Add +7.2% | 867,461 | $88.6M |
| Pictet Asset Management Holding SA | 0.09% | Reduce -62.3% | 864,737 | $88.2M |
| CIBC Bancorp USA Inc. | 0.11% | — | 828,793 | $84.6M |
| American Century Companies Inc. | 0.04% | Add +106.1% | 815,792 | $83.3M |
| UBS Group AG | 0.01% | Add +0.7% | 801,430 | $81.9M |
| Jane Street Group, LLC | 0.08% | New | 707,441 | $72.3M |
| APG Asset Management US Inc. | 0.55% | Add +20.9% | 703,912 | $71.1M |
| Barclays PLC | 0.02% | Reduce -7.6% | 673,771 | $68.8M |
| Wells Fargo & Company | 0.01% | Add +3.3% | 658,454 | $67.3M |
| Welch & Forbes LLC | 0.86% | Reduce -0.7% | 652,068 | $66.6M |
| Vanguard Global Advisers, LLC | 0.04% | — | 647,775 | $66.2M |
| LPL Financial LLC | 0.02% | Reduce -2.1% | 621,238 | $63.5M |
| Epoch Investment Partners, Inc. | 0.38% | Reduce -2.1% | 616,513 | $63.0M |
| T. Rowe Price Associates Inc. | 0.01% | Reduce -0.9% | 601,581 | $61.4M |
| Universal- Beteiligungs- und Servicegesellschaft mbH | 0.11% | Reduce -5.6% | 590,504 | $60.3M |
| Adage Capital Partners Gp, L.L.C. | 0.09% | Reduce -10.2% | 590,052 | $60.3M |
| Nomura Asset Management International Inc. | 0.10% | Add +596.8% | 586,881 | $59.9M |
| Rhumbline Advisers | 0.05% | Reduce -2.0% | 578,543 | $59.1M |
| Nomura Asset Management Co. Ltd. | 0.15% | Add +3.5% | 563,343 | $57.5M |
| Worldquant Millennium Advisors LLC | 0.22% | Add +251.2% | 548,049 | $56.0M |
| Asset Management One Co., Ltd. | 0.16% | Reduce -1.5% | 547,474 | $55.9M |
| Baron Capital (BAMCO) | 0.16% | New | 525,270 | $53.7M |
| BNP Paribas Financial Markets | 0.03% | Reduce -9.6% | 508,511 | $51.9M |
| VANGUARD ASSET MANAGEMENT, Ltd | 0.04% | — | 504,995 | $51.6M |
| DigitalBridge Group, Inc. | 3.28% | New | 504,021 | $51.5M |
| California Public Employees Retirement System | 0.03% | Reduce -2.2% | 502,460 | $51.3M |
| Border to Coast Pensions Partnership Ltd | 0.81% | Reduce -6.0% | 470,000 | $48.2M |
| Clark Capital Management Group, Inc. | 0.30% | New | 468,365 | $47.8M |
| Alliancebernstein L.P. | 0.02% | Add +3.8% | 565,255 | $46.9M |
| VIRGINIA RETIREMENT SYSTEMS ET Al | 0.33% | Add +252.7% | 440,108 | $45.0M |
| National Pension Service | 0.03% | Reduce -15.6% | 429,392 | $43.9M |
| Public Employees Retirement System of Ohio | 0.14% | Add +121.3% | 423,714 | $43.3M |
| California State Teachers Retirement System | 0.05% | Reduce -2.6% | 422,871 | $43.2M |
| Bank of Montreal | 0.02% | Reduce -7.0% | 406,013 | $41.5M |
| Teacher Retirement System of Texas | 0.17% | Add +18.2% | 394,701 | $40.3M |
| Rockefeller Capital Management L.P. | 0.07% | Reduce -3.7% | 389,140 | $39.7M |
| Point72 Asset Management | 0.07% | Reduce -52.2% | 377,618 | $38.6M |
| Citadel Advisors | 0.03% | Reduce -66.5% | 374,954 | $38.3M |
| Millennium Management | 0.03% | Reduce -23.4% | 374,463 | $38.2M |
| Aberdeen Group plc | 0.06% | Add +1.7% | 371,208 | $37.9M |
| Neuberger Berman Group LLC | 0.03% | Reduce -16.4% | 360,751 | $36.8M |
| Adelante Capital Management LLC | 2.49% | Add +5.2% | 356,934 | $36.5M |
| Wellington Management Group LLP | 0.01% | Add +234.1% | 347,915 | $35.5M |
| Vanguard Investments Australia, Ltd. | 0.10% | — | 343,334 | $35.1M |
| CANADA LIFE ASSURANCE Co | 0.06% | Reduce -0.3% | 335,860 | $34.4M |
| Quantinno Capital Management LP | 0.05% | Add +92.7% | 322,017 | $32.9M |
| Adell Harriman & Carpenter Inc. | 1.97% | Add +0.4% | 315,817 | $32.3M |
| Citigroup Inc. | 0.02% | Reduce -0.9% | 315,634 | $32.2M |
| Marble Harbor Investment Counsel, LLC | 3.33% | Reduce -4.3% | 300,474 | $30.7M |
| Ensign Peak Advisors, Inc | 0.06% | Add +298.5% | 297,330 | $30.4M |
| Raymond James Financial Inc. | 0.01% | Reduce -19.4% | 295,133 | $30.1M |
| STRS Ohio | 0.12% | Reduce -30.5% | 287,817 | $29.4M |
| Macquarie Group Ltd. | 0.16% | Reduce -7.6% | 270,616 | $27.6M |
| Apollo Management Holdings, L.P. | 0.53% | No change | 265,539 | $27.1M |
| Aviva PLC | 0.05% | Add +2.8% | 263,200 | $26.9M |
| State Board of Administration of Florida Retirement System | 0.05% | No change | 262,515 | $26.8M |
| Swedbank AB | 0.03% | Reduce -8.6% | 260,330 | $26.6M |
| Cetera Investment Advisers | 0.03% | Add +4.6% | 260,039 | $26.6M |
| Heitman Real Estate Securities LLC | 1.91% | Reduce -47.1% | 259,594 | $26.5M |
| Stifel Financial Corp. | 0.02% | Add +12.4% | 255,348 | $26.1M |
"% of holder's portfolio" is IRM's weight in each manager's 13F, not the share of Iron Mountain Inc. the manager owns.