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IRM · Iron Mountain Inc

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$122.08 -4.59 (-3.62%) At close · Aug 19
Market Cap
$36.34B
Shares
297.70M

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Holders: 1,158
Total Value: $32,634,107,663
Total Shares: 259,486,796

Institutional Ownership Trend

26 quarters

Holder Concentration

Across 1,158 13F filers · Δ vs Mar 31, 2026
Top Holder
13.0%
Sep 2023 → Jun 2026 · range 12.9% – 20.1%
+0.1 pts
Top 5
41.7%
Sep 2023 → Jun 2026 · range 41.7% – 49.2%
−1.4 pts
Top 10
53.3%
Sep 2023 → Jun 2026 · range 53.3% – 57.5%
−1.4 pts
HHI
447
Sep 2023 → Jun 2026 · range 447 – 685
Broadly held−9

Quarterly Activity

vs Mar 31, 2026
New
148
Increased
444
Decreased
381
Sold Out
87
Unchanged
185
Holder count: +61
Institutional value: +24.6%
Shares held: +1.2%

Top Buyers

vs Mar 31, 2026
Institution Added Now Holds Open

Top Sellers

vs Mar 31, 2026
Institution Sold Now Holds Open

Top New Positions

vs Mar 31, 2026
Institution Acquired Value (USD) Open

Top Sold-Out Positions

vs Mar 31, 2026
Institution Previously Held Last Value (USD) Open
Showing 100 of 1,187
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Holder Value (USD) % of 13F Shares Open
Key facts CIK 1020569 CUSIP 46284V101 13F (30d) 1021 filings 986 filers Visit website Investor relations