Merck
MRK
3,672 hedge funds and large institutions have $206B invested in Merck in 2025 Q4 according to their latest regulatory filings, with 556 funds opening new positions, 1,378 increasing their positions, 1,403 reducing their positions, and 131 closing their positions.
324% more first-time investments, than exits
New positions opened: 556 | Existing positions closed: 131
67% more funds holding in top 10
Funds holding in top 10: 46 → 77 (+31)
43% more call options, than puts
Call options by funds: $3.76B | Put options by funds: $2.62B
29% more capital invested
Capital invested by funds: $160B → $206B (+$46.6B)
11% more funds holding
Funds holding: 3,318 → 3,672 (+354)
2.69% more ownership
Funds ownership: 76.24% → 78.92% (+2.7%)
2% less repeat investments, than reductions
Existing positions increased: 1,378 | Existing positions reduced: 1,403
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Wellington Management Group
Boston,
Massachusetts
|
+$1.05B |
| 2 |
Fidelity Investments
Boston,
Massachusetts
|
+$696M |
| 3 |
Millennium Management
New York
|
+$567M |
| 4 |
Citadel Advisors
Miami,
Florida
|
+$549M |
| 5 |
Jennison Associates
New York
|
+$522M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Arrowstreet Capital
Boston,
Massachusetts
|
-$823M |
| 2 |
JP Morgan Chase
New York
|
-$563M |
| 3 |
Charles Schwab
San Francisco,
California
|
-$482M |
| 4 |
Assenagon Asset Management
Senningerberg,
Luxembourg
|
-$465M |
| 5 |
ClearBridge Investments
New York
|
-$410M |
MRK Hedge Fund Activity: Q4 2025 in Review
3,672 of the 8,284 institutional investors tracked by Wall St. Rank reported a position in Merck (MRK) for Q4 2025, worth a combined $206B — up 29% from $160B a quarter earlier.
Buyers outnumbered sellers: 556 funds opened new MRK positions and 131 closed out — a net gain of 425 holders — while 1,378 added to existing stakes and 1,403 trimmed.
The largest buyer was Wellington Management Group, adding an estimated $1.05B. The largest seller was Arrowstreet Capital, cutting an estimated $823M.
- 3,672 institutional investors held Merck (MRK) as of Q4 2025, up from 3,318 in Q3 2025.
- Funds reported $206B of Merck stock for Q4 2025, up 29% quarter-over-quarter.
- 556 funds opened new Merck positions in Q4 2025 and 131 closed out, a net change of +425 holders.
- The largest Merck buyer in Q4 2025 was Wellington Management Group, an estimated $1.05B added.
- The largest Merck seller in Q4 2025 was Arrowstreet Capital, an estimated $823M sold.
Based on aggregated 13F filings for Q4 2025.