Who owns Iron Mountain (IRM)
Which tracked institutional funds hold IRM, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See IRM company fundamentals →
Ownership as of the 2026-Q2 13F filings (latest filed 2026-09-22). 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
The tracked-fund tape on IRM is one-sided between 2026-Q1 and 2026-Q2: 414 added or opened and 110 trimmed or exited — on balance accumulating.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
IRM’s largest tracked holder by dollar value, BlackRock, Inc., sizes it at 0.1% of its own reported 13F book, while the median holder sizes it at 0.1% of theirs — a 0.0pp gap the other way — the median holder sizes IRM more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in IRM divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2026-Q1 and 2026-Q2, across 1097 tracked filers holding IRM, 564 increased or opened the position and 499 reduced or closed it; over the same quarter, open-market insider Form 4s were net sales.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in IRM between the 2026-Q1 and 2026-Q2 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 38
- VOLORIDGE INVESTMENT MANAGEMENT, LLC$52M
- SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC$30M
- Nykredit A/S$15M
- O'Neil Global Advisors, Inc.$14M
- Uniplan Investment Counsel, Inc.$12M
- BAROMETER CAPITAL MANAGEMENT INC.$8M
Full exits 65
- COHEN & STEERS, INC.$1.7B
- PGGM Investments$140M
- DekaBank Deutsche Girozentrale$117M
- Amundi$111M
- Epoch Investment Partners, Inc.$63M
- Border to Coast Pensions Partnership Ltd$48M
Largest adds
- BlackRock, Inc.$1.6B
- VANGUARD PORTFOLIO MANAGEMENT LLC$675M
- VANGUARD CAPITAL MANAGEMENT LLC$478M
- STATE STREET CORP$434M
- UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC$402M
- FMR LLC$230M
Largest trims
- Daiwa Securities Group Inc.$82M
- Capital World Investors$37M
- Point72 Asset Management, L.P.$23M
- JANE STREET GROUP, LLC$22M
- Schonfeld Strategic Advisors LLC$20M
- Brookfield Corp /ON/$19M
Institutional holders
One row per tracked fund, most shares held first (every row is from one quarter; reported value breaks ties). “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding.
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. added | 33,570,910 | $4.2B | 15.5% | 2026-Q2 |
| VANGUARD PORTFOLIO MANAGEMENT LLC added | 25,568,944 | $3.2B | 11.8% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC added | 18,953,705 | $2.4B | 8.7% | 2026-Q2 |
| STATE STREET CORP added | 17,634,044 | $2.2B | 8.2% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC added | 8,649,249 | $1.1B | 4.0% | 2026-Q2 |
| FMR LLC added | 7,872,365 | $994M | 3.6% | 2026-Q2 |
| DIMENSIONAL FUND ADVISORS LP added | 4,625,684 | $584M | 2.1% | 2026-Q2 |
| MORGAN STANLEY trimmed | 4,426,922 | $559M | 2.0% | 2026-Q2 |
| PRINCIPAL FINANCIAL GROUP INC trimmed | 4,373,424 | $552M | 2.0% | 2026-Q2 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 4,263,487 | $539M | 2.0% | 2026-Q2 |
| NORTHERN TRUST CORP added | 4,222,967 | $533M | 1.9% | 2026-Q2 |
| NORGES BANK added | 4,214,697 | $532M | 1.9% | 2026-Q2 |
| Invesco Ltd. added | 4,065,649 | $514M | 1.9% | 2026-Q2 |
| Legal & General Group Plc added | 3,244,741 | $410M | 1.5% | 2026-Q2 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 3,193,560 | $403M | 1.5% | 2026-Q2 |
| DEUTSCHE BANK AG\ trimmed | 3,049,079 | $385M | 1.4% | 2026-Q2 |
| GOLDMAN SACHS GROUP INC added | 2,822,732 | $357M | 1.3% | 2026-Q2 |
| CENTERSQUARE INVESTMENT MANAGEMENT LLC added | 2,323,974 | $294M | 1.1% | 2026-Q2 |
| Nuveen, LLC added | 2,218,771 | $280M | 1.0% | 2026-Q2 |
| JPMORGAN CHASE & CO added | 2,212,137 | $288M | 1.0% | 2026-Q2 |
| AQR CAPITAL MANAGEMENT LLC added | 2,127,095 | $267M | 1.0% | 2026-Q2 |
| PRUDENTIAL FINANCIAL INC trimmed | 1,974,079 | $249M | 0.9% | 2026-Q2 |
| Vontobel Holding Ltd. trimmed | 1,919,656 | $242M | 0.9% | 2026-Q2 |
| Daiwa Securities Group Inc. trimmed | 1,861,547 | $235M | 0.9% | 2026-Q2 |
| AMERIPRISE FINANCIAL INC trimmed | 1,668,337 | $211M | 0.8% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO added | 1,658,635 | $210M | 0.8% | 2026-Q2 |
| ROYAL BANK OF CANADA added | 1,640,511 | $207M | 0.8% | 2026-Q2 |
| Bank of New York Mellon Corp trimmed | 1,600,078 | $202M | 0.7% | 2026-Q2 |
| DUFF & PHELPS INVESTMENT MANAGEMENT CO trimmed | 1,455,435 | $184M | 0.7% | 2026-Q2 |
| Russell Investments Group, Ltd. trimmed | 1,403,623 | $177M | 0.6% | 2026-Q2 |
| HSBC HOLDINGS PLC added | 1,347,871 | $170M | 0.6% | 2026-Q2 |
| Contour Asset Management LLC trimmed | 1,274,684 | $161M | 0.6% | 2026-Q2 |
| Capital World Investors trimmed | 1,217,169 | $154M | 0.6% | 2026-Q2 |
| AMERICAN CENTURY COMPANIES INC added | 1,154,487 | $146M | 0.5% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ trimmed | 1,118,827 | $141M | 0.5% | 2026-Q2 |
| CBRE INVESTMENT MANAGEMENT LISTED REAL ASSETS LLC trimmed | 1,072,881 | $136M | 0.5% | 2026-Q2 |
| Mitsubishi UFJ Asset Management Co., Ltd. added | 982,596 | $124M | 0.5% | 2026-Q2 |
| UBS Group AG added | 915,101 | $116M | 0.4% | 2026-Q2 |
| Sumitomo Mitsui Trust Group, Inc. trimmed | 896,560 | $113M | 0.4% | 2026-Q2 |
| Swiss National Bank trimmed | 839,061 | $106M | 0.4% | 2026-Q2 |
| Pictet Asset Management Holding SA trimmed | 817,622 | $103M | 0.4% | 2026-Q2 |
| CIBC Bancorp USA Inc. trimmed | 777,480 | $98M | 0.4% | 2026-Q2 |
| BARCLAYS PLC added | 743,343 | $94M | 0.3% | 2026-Q2 |
| APG Asset Management US Inc. | 703,912 | $86M | 0.3% | 2026-Q2 |
| SEI INVESTMENTS CO trimmed | 697,737 | $88M | 0.3% | 2026-Q2 |
| Aberdeen Group plc added | 691,514 | $87M | 0.3% | 2026-Q2 |
| WELLS FARGO & COMPANY/MN added | 662,157 | $84M | 0.3% | 2026-Q2 |
| BNP PARIBAS FINANCIAL MARKETS added | 648,227 | $82M | 0.3% | 2026-Q2 |
| Vanguard Global Advisers, LLC trimmed | 641,901 | $81M | 0.3% | 2026-Q2 |
| LPL Financial LLC added | 640,383 | $81M | 0.3% | 2026-Q2 |
| Welch & Forbes LLC trimmed | 639,322 | $81M | 0.3% | 2026-Q2 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 634,613 | $80M | 0.3% | 2026-Q2 |
| Universal- Beteiligungs- und Servicegesellschaft mbH added | 610,889 | $77M | 0.3% | 2026-Q2 |
| Quantinno Capital Management LP added | 590,647 | $75M | 0.3% | 2026-Q2 |
| NOMURA ASSET MANAGEMENT CO LTD added | 588,384 | $74M | 0.3% | 2026-Q2 |
| RHUMBLINE ADVISERS trimmed | 573,267 | $72M | 0.3% | 2026-Q2 |
| VANGUARD ASSET MANAGEMENT, Ltd added | 568,845 | $72M | 0.3% | 2026-Q2 |
| ALLIANCEBERNSTEIN L.P. trimmed | 562,711 | $57M | 0.2% | 2026-Q2 |
| RAYMOND JAMES FINANCIAL INC added | 561,539 | $71M | 0.3% | 2026-Q2 |
| Asset Management One Co., Ltd. added | 554,607 | $70M | 0.3% | 2026-Q2 |
| California Public Employees Retirement System added | 553,872 | $70M | 0.3% | 2026-Q2 |
| NOMURA ASSET MANAGEMENT INTERNATIONAL INC. trimmed | 552,190 | $70M | 0.3% | 2026-Q2 |
| WORLDQUANT MILLENNIUM ADVISORS LLC trimmed | 537,162 | $68M | 0.2% | 2026-Q2 |
| ADAGE CAPITAL PARTNERS GP, L.L.C. trimmed | 535,152 | $68M | 0.2% | 2026-Q2 |
| WELLINGTON MANAGEMENT GROUP LLP added | 512,906 | $65M | 0.2% | 2026-Q2 |
| Clark Capital Management Group, Inc. added | 476,766 | $60M | 0.2% | 2026-Q2 |
| DigitalBridge Group, Inc. trimmed | 457,126 | $58M | 0.2% | 2026-Q2 |
| National Pension Service added | 454,815 | $57M | 0.2% | 2026-Q2 |
| BANK OF MONTREAL /CAN/ added | 453,715 | $57M | 0.2% | 2026-Q2 |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND added | 443,901 | $56M | 0.2% | 2026-Q2 |
| VIRGINIA RETIREMENT SYSTEMS ET Al added | 441,803 | $56M | 0.2% | 2026-Q2 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM added | 434,529 | $55M | 0.2% | 2026-Q2 |
| PUBLIC EMPLOYEES RETIREMENT SYSTEM OF OHIO trimmed | 422,586 | $53M | 0.2% | 2026-Q2 |
| CITIGROUP INC added | 422,524 | $53M | 0.2% | 2026-Q2 |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC added | 412,748 | $52M | 0.2% | 2026-Q2 |
| JANE STREET GROUP, LLC trimmed | 396,541 | $50M | 0.2% | 2026-Q2 |
| Rockefeller Capital Management L.P. added | 391,620 | $49M | 0.2% | 2026-Q2 |
| Heitman Real Estate Securities LLC added | 357,721 | $45M | 0.2% | 2026-Q2 |
| Vanguard Investments Australia, Ltd. added | 347,312 | $44M | 0.2% | 2026-Q2 |
| CITADEL ADVISORS LLC trimmed | 343,168 | $43M | 0.2% | 2026-Q2 |
| Adelante Capital Management LLC trimmed | 325,641 | $41M | 0.2% | 2026-Q2 |
| ADELL HARRIMAN & CARPENTER INC added | 316,465 | $40M | 0.1% | 2026-Q2 |
| BAMCO INC /NY/ trimmed | 310,721 | $39M | 0.1% | 2026-Q2 |
| Robeco Institutional Asset Management B.V. added | 297,899 | $38M | 0.1% | 2026-Q2 |
| TEACHER RETIREMENT SYSTEM OF TEXAS trimmed | 297,427 | $38M | 0.1% | 2026-Q2 |
| Marble Harbor Investment Counsel, LLC trimmed | 295,533 | $37M | 0.1% | 2026-Q2 |
| NEUBERGER BERMAN GROUP LLC trimmed | 290,384 | $37M | 0.1% | 2026-Q2 |
| Swedbank AB added | 287,064 | $36M | 0.1% | 2026-Q2 |
| COMMONWEALTH OF PENNSYLVANIA PUBLIC SCHOOL EMPLS RETRMT SYS added | 286,428 | $36M | 0.1% | 2026-Q2 |
| MACQUARIE GROUP LTD added | 275,969 | $35M | 0.1% | 2026-Q2 |
| VICTORY CAPITAL MANAGEMENT INC added | 268,209 | $34M | 0.1% | 2026-Q2 |
| Apollo Management Holdings, L.P. | 265,539 | $34M | 0.1% | 2026-Q2 |
| AVIVA PLC trimmed | 260,627 | $33M | 0.1% | 2026-Q2 |
| STIFEL FINANCIAL CORP added | 259,638 | $33M | 0.1% | 2026-Q2 |
| STATE BOARD OF ADMINISTRATION OF FLORIDA RETIREMENT SYSTEM trimmed | 257,566 | $33M | 0.1% | 2026-Q2 |
| Cetera Investment Advisers trimmed | 257,097 | $32M | 0.1% | 2026-Q2 |
| FEDERATED HERMES, INC. added | 241,777 | $31M | 0.1% | 2026-Q2 |
| Americana Partners, LLC trimmed | 241,330 | $30M | 0.1% | 2026-Q2 |
| SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC added | 235,567 | $30M | 0.1% | 2026-Q2 |
| Retirement Systems of Alabama trimmed | 227,483 | $29M | 0.1% | 2026-Q2 |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.