Iron Mountain
1,020 hedge funds and large institutions have $25.5B invested in Iron Mountain in 2025 Q3 according to their latest regulatory filings, with 76 funds opening new positions, 370 increasing their positions, 392 reducing their positions, and 89 closing their positions.
10% more capital inflows, than outflows
Capital inflows: $1.56B | Capital outflows: $1.42B
0.4% more ownership
Funds ownership: 84.34% → 84.75% (+0.4%)
6% less repeat investments, than reductions
Existing positions increased: 370 | Existing positions reduced: 392
6% less call options, than puts
Call options by funds: $103M | Put options by funds: $110M
3% less funds holding
Funds holding: 1,047 → 1,020 (-27)
15% less first-time investments, than exits
New positions opened: 76 | Existing positions closed: 89
19% less funds holding in top 10
Funds holding in top 10: 16 → 13 (-3)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
UBS AM
Chicago,
Illinois
|
+$261M |
| 2 |
Cohen & Steers
New York
|
+$191M |
| 3 |
Fidelity Investments
Boston,
Massachusetts
|
+$112M |
| 4 |
Vontobel Holding
Zurich,
Switzerland
|
+$104M |
| 5 |
CAM
Contour Asset Management
New York
|
+$80M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Wellington Management Group
Boston,
Massachusetts
|
-$120M |
| 2 |
Zurich Insurance Group
Zurich,
Switzerland
|
-$52.7M |
| 3 |
Deutsche Bank
Frankfurt Am Main Ge,
Germany
|
-$51.9M |
| 4 |
Goldman Sachs
New York
|
-$50.7M |
| 5 |
Amundi
Paris,
France
|
-$49.7M |
IRM Hedge Fund Activity: Q3 2025 in Review
1,020 of the 7,657 institutional investors tracked by Wall St. Rank reported a position in Iron Mountain (IRM) for Q3 2025, worth a combined $25.5B — down 0.02% from $25.5B a quarter earlier.
Sellers outnumbered buyers: 89 funds closed out of IRM and 76 opened new positions — a net loss of 13 holders — while 392 trimmed existing stakes and 370 added.
The largest buyer was UBS AM, adding an estimated $261M. The largest seller was Wellington Management Group, cutting an estimated $120M.
- 1,020 institutional investors held Iron Mountain (IRM) as of Q3 2025, down from 1,047 in Q2 2025.
- Funds reported $25.5B of Iron Mountain stock for Q3 2025, down 0.02% quarter-over-quarter.
- 76 funds opened new Iron Mountain positions in Q3 2025 and 89 closed out, a net change of -13 holders.
- The largest Iron Mountain buyer in Q3 2025 was UBS AM, an estimated $261M added.
- The largest Iron Mountain seller in Q3 2025 was Wellington Management Group, an estimated $120M sold.
Based on aggregated 13F filings for Q3 2025.