Latest Period
Q1 2026
Security Snapshot
IRON MOUNTAIN INC - Common Stock (IRM) Institutional Ownership
CUSIP: 46284V101
13F Institutional Holders and Ownership History from Q1 2014 to Q2 2026
Institutions Reporting
1,080
Shares (Excl. Options)
252,774,606
Price
$102.14
Save this security page for your next review
Keep this CUSIP in your watchlists so you can revisit quarter changes from one place. If you create an account from here, we will bring you back after verification.
- Security type / class
- Equity / Common Stock
- Symbol
- IRM on NYSE
- All holders as of 31 Mar 2026
- Q1 2026
- Total 13F shares
- 252,774,606
- Total 13F value
- $25,802,908,224
- Portfolio coverage rank
- 0.02%
- Share change
- -3,950,033
- Value change
- -$296,288,752
- Number of holders
- 1,080
- Shares outstanding
- 297,661,125
- SEC-reported price per share
- $126.31
- Insider filing price
- $126.31
Latest holder snapshot
5 signals
Issuer context
Names, identifiers, and filing context for this profile.
3 identity fields
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Key facts
- IRM - IRON MOUNTAIN INC - Common Stock is tracked under CUSIP 46284V101.
- 1080 institutions reported positions in Q1 2026.
- 3 significant owners is listed from Schedule 13D/13G reporting.
Change
- Holder count moved from 1,080 to 74 between Q1 2026 and Q2 2026.
- SEC-reported value moved from $25,802,908,224 to $118,858,931.
Research use
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Evidence
Source: SEC Form 13F
Open SEC evidence
Latest holder context comes from 1080 institutions filings for Q1 2026.
Security key
46284V101
Latest holder period
Q1 2026
13F holders
1,080
13D/G owners
3
CIK / CUSIP context first
Open Q1 2026 holders
IRM full holder history
IRON MOUNTAIN INC SEC filings
IRON MOUNTAIN INC company facts
IRON MOUNTAIN INC insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 46284V101:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
3
Security
IRM
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| VANGUARD PORTFOLIO MANAGEMENT LLC | 8.4% | $2,558,722,929 | 25,051,135 | Vanguard Portfolio Management | 31 Mar 2026 | |||
| VANGUARD CAPITAL MANAGEMENT LLC | 7.4% | $2,234,037,028 | 21,872,303 | Vanguard Capital Management | 31 Mar 2026 | |||
| COHEN & STEERS, INC. | 4.9% | -26% | $1,503,596,476 | -$470,109,106 | 14,555,629 | -24% | Cohen & Steers, Inc. | 30 Apr 2026 |
As of 31 Mar 2026, 1,080 institutional investors reported holding 252,774,606 shares of IRON MOUNTAIN INC - Common Stock (IRM). This represents 85% of the company’s total 297,661,125 outstanding shares.
13F concentration
Top 25 institutional shareholders
Largest 13F positions for this security by reported shares and value.
Top holder share
61%
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| BlackRock, Inc. | 11% | 33,021,354 | +0.31% | 0.06% | $3,372,801,141 |
| VANGUARD PORTFOLIO MANAGEMENT LLC | 8.4% | 25,015,557 | 0% | 0.13% | $2,555,088,992 |
| VANGUARD CAPITAL MANAGEMENT LLC | 6.3% | 18,758,889 | 0% | 0.05% | $1,916,032,922 |
| STATE STREET CORP | 5.9% | 17,551,633 | +3.9% | 0.06% | $1,807,660,367 |
| COHEN & STEERS, INC. | 5.4% | 16,169,341 | -14% | 2.9% | $1,651,537,000 |
| GEODE CAPITAL MANAGEMENT, LLC | 2.9% | 8,486,127 | +2.3% | 0.05% | $863,699,269 |
| FMR LLC | 2.5% | 7,484,398 | -6.3% | 0.04% | $764,456,401 |
| MORGAN STANLEY | 1.6% | 4,652,247 | +29% | 0.03% | $475,180,655 |
| PRINCIPAL FINANCIAL GROUP INC | 1.5% | 4,566,093 | +8.5% | 0.25% | $466,382,473 |
| DIMENSIONAL FUND ADVISORS LP | 1.5% | 4,552,286 | +2.8% | 0.1% | $464,930,903 |
| NORTHERN TRUST CORP | 1.4% | 4,150,486 | -0.05% | 0.06% | $423,930,638 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 1.3% | 4,013,007 | +3.4% | 0.06% | $409,888,535 |
| Invesco Ltd. | 1.3% | 3,921,521 | -11% | 0.06% | $400,544,198 |
| Legal & General Group Plc | 1.1% | 3,135,074 | -6.6% | 0.07% | $320,216,461 |
| Daiwa Securities Group Inc. | 1% | 3,107,440 | -15% | 0.92% | $317,393,921 |
| DEUTSCHE BANK AG\ | 1% | 3,092,084 | +22% | 0.1% | $315,825,461 |
| PRUDENTIAL FINANCIAL INC | 0.81% | 2,416,063 | +4.6% | 0.3% | $246,776,675 |
| CENTERSQUARE INVESTMENT MANAGEMENT LLC | 0.78% | 2,310,045 | -12% | 2.4% | $235,947,996 |
| GOLDMAN SACHS GROUP INC | 0.74% | 2,216,672 | +45% | 0.03% | $226,410,923 |
| JPMORGAN CHASE & CO | 0.71% | 2,123,358 | +10% | 0.01% | $207,239,854 |
| Vontobel Holding Ltd. | 0.71% | 2,116,877 | +25% | 0.74% | $216,217,815 |
| Nuveen, LLC | 0.69% | 2,068,408 | -2.8% | 0.06% | $211,267,193 |
| Capital World Investors | 0.63% | 1,867,169 | -12% | 0.03% | $190,712,642 |
| AMERIPRISE FINANCIAL INC | 0.62% | 1,851,007 | +6.1% | 0.04% | $189,082,930 |
| AQR CAPITAL MANAGEMENT LLC | 0.62% | 1,846,073 | +100% | 0.08% | $183,074,982 |
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
50
Latest
Q1 2026
Rows shown
1-25 of 50
| Period | 13F Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q2 | 941,579 | $118,858,931 | +$6,612,121 | $126.31 | 74 |
| 2026 Q1 | 252,774,606 | $25,802,908,224 | -$296,288,752 | $102.14 | 1,080 |
| 2025 Q4 | 257,162,908 | $21,344,532,604 | +$502,933,470 | $82.95 | 1,003 |
| 2025 Q3 | 250,099,173 | $25,501,731,178 | +$119,529,096 | $101.94 | 1,008 |
| 2025 Q2 | 248,525,285 | $25,494,373,784 | +$803,176,666 | $102.57 | 1,032 |
| 2025 Q1 | 240,934,690 | $20,734,604,323 | +$263,720,115 | $86.04 | 981 |
| 2024 Q4 | 236,810,872 | $24,896,739,978 | -$607,469,785 | $105.11 | 1,052 |
| 2024 Q3 | 241,814,752 | $28,741,204,354 | -$1,107,026,346 | $118.83 | 1,044 |
| 2024 Q2 | 247,404,957 | $22,194,271,901 | +$1,038,973,385 | $89.62 | 958 |
| 2024 Q1 | 236,401,763 | $18,948,590,587 | +$213,667,716 | $80.21 | 929 |
| 2023 Q4 | 233,491,997 | $16,340,519,763 | +$271,706,582 | $69.98 | 884 |
| 2023 Q3 | 229,526,142 | $13,658,760,340 | +$171,582,469 | $59.45 | 826 |
| 2023 Q2 | 226,655,213 | $12,884,186,843 | +$83,715,858 | $56.82 | 805 |
| 2023 Q1 | 224,502,203 | $11,873,411,821 | -$142,387,662 | $52.91 | 778 |
| 2022 Q4 | 227,868,373 | $11,377,567,891 | +$44,555,254 | $49.85 | 773 |
| 2022 Q3 | 226,777,832 | $9,985,042,681 | +$96,567,031 | $43.97 | 731 |
| 2022 Q2 | 224,032,661 | $10,915,712,274 | -$16,300,595 | $48.69 | 755 |
| 2022 Q1 | 224,442,000 | $12,439,113,556 | -$172,066,245 | $55.41 | 765 |
| 2021 Q4 | 227,876,068 | $11,926,247,380 | -$32,879,189 | $52.33 | 735 |
| 2021 Q3 | 228,189,194 | $9,924,915,322 | -$6,524,012 | $43.45 | 693 |
| 2021 Q2 | 228,564,720 | $9,682,737,503 | +$46,970,021 | $42.32 | 674 |
| 2021 Q1 | 227,132,792 | $8,414,631,609 | -$145,818,371 | $37.01 | 611 |
| 2020 Q4 | 231,708,448 | $6,837,063,849 | -$283,592,825 | $29.48 | 591 |
| 2020 Q3 | 242,359,753 | $6,501,463,965 | -$98,472,508 | $26.79 | 576 |
| 2020 Q2 | 245,858,050 | $6,425,333,738 | +$15,126,586 | $26.10 | 547 |