Iron Mountain
1,012 hedge funds and large institutions have $21.4B invested in Iron Mountain in 2025 Q4 according to their latest regulatory filings, with 122 funds opening new positions, 327 increasing their positions, 407 reducing their positions, and 106 closing their positions.
62% more call options, than puts
Call options by funds: $114M | Put options by funds: $70.6M
15% more first-time investments, than exits
New positions opened: 122 | Existing positions closed: 106
2.29% more ownership
Funds ownership: 84.75% → 87.04% (+2.3%)
0% less funds holding
Funds holding: 1,017 → 1,012 (-5)
16% less capital invested
Capital invested by funds: $25.5B → $21.4B (-$4.17B)
20% less repeat investments, than reductions
Existing positions increased: 327 | Existing positions reduced: 407
46% less funds holding in top 10
Funds holding in top 10: 13 → 7 (-6)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Cohen & Steers
New York
|
+$295M |
| 2 |
Principal Financial Group
Des Moines,
Iowa
|
+$157M |
| 3 |
BlackRock
New York
|
+$113M |
| 4 |
Citadel Advisors
Miami,
Florida
|
+$99M |
| 5 |
Vontobel Holding
Zurich,
Switzerland
|
+$57.2M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
UBS AM
Chicago,
Illinois
|
-$296M |
| 2 |
Royal Bank of Canada
Toronto,
Ontario, Canada
|
-$94.8M |
| 3 |
Invesco
Atlanta,
Georgia
|
-$60.8M |
| 4 |
UBS Group
Zurich,
Switzerland
|
-$59.9M |
| 5 |
Vanguard Group
Malvern,
Pennsylvania
|
-$58.6M |
IRM Hedge Fund Activity: Q4 2025 in Review
1,012 of the 8,284 institutional investors tracked by Wall St. Rank reported a position in Iron Mountain (IRM) for Q4 2025, worth a combined $21.4B — down 16% from $25.5B a quarter earlier.
Buyers outnumbered sellers: 122 funds opened new IRM positions and 106 closed out — a net gain of 16 holders — while 327 added to existing stakes and 407 trimmed.
The largest buyer was Cohen & Steers, adding an estimated $295M. The largest seller was UBS AM, cutting an estimated $296M.
- 1,012 institutional investors held Iron Mountain (IRM) as of Q4 2025, down from 1,017 in Q3 2025.
- Funds reported $21.4B of Iron Mountain stock for Q4 2025, down 16% quarter-over-quarter.
- 122 funds opened new Iron Mountain positions in Q4 2025 and 106 closed out, a net change of +16 holders.
- The largest Iron Mountain buyer in Q4 2025 was Cohen & Steers, an estimated $295M added.
- The largest Iron Mountain seller in Q4 2025 was UBS AM, an estimated $296M sold.
Based on aggregated 13F filings for Q4 2025.