Biogen
BIIB
869 hedge funds and large institutions have $16.3B invested in Biogen in 2025 Q2 according to their latest regulatory filings, with 94 funds opening new positions, 342 increasing their positions, 267 reducing their positions, and 102 closing their positions.
150% more funds holding in top 10
Funds holding in top 10: 2 → 5 (+3)
28% more repeat investments, than reductions
Existing positions increased: 342 | Existing positions reduced: 267
14% more call options, than puts
Call options by funds: $381M | Put options by funds: $333M
2% more capital inflows, than outflows
Capital inflows: $1.49B | Capital outflows: $1.47B
0.04% less ownership
Funds ownership: 88.84% → 88.8% (-0.04%)
8% less first-time investments, than exits
New positions opened: 94 | Existing positions closed: 102
2% less funds holding
Funds holding: 887 → 869 (-18)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Point72 Asset Management
Stamford,
Connecticut
|
+$427M |
| 2 |
Alyeska Investment Group
Chicago,
Illinois
|
+$63.4M |
| 3 |
Arrowstreet Capital
Boston,
Massachusetts
|
+$51M |
| 4 |
Fidelity Investments
Boston,
Massachusetts
|
+$45.5M |
| 5 |
AustralianSuper
Melbourne,
Australia
|
+$42.6M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
BlackRock
New York
|
-$206M |
| 2 |
T. Rowe Price Investment Management
Baltimore,
Maryland
|
-$158M |
| 3 |
Amundi
Paris,
France
|
-$91.7M |
| 4 |
SG Americas Securities
New York
|
-$86.9M |
| 5 |
Qube Research & Technologies (QRT)
London,
United Kingdom
|
-$60.2M |
BIIB Hedge Fund Activity: Q2 2025 in Review
869 of the 7,627 institutional investors tracked by Wall St. Rank reported a position in Biogen (BIIB) for Q2 2025, worth a combined $16.3B — down 8.1% from $17.8B a quarter earlier.
Sellers outnumbered buyers: 102 funds closed out of BIIB and 94 opened new positions — a net loss of 8 holders — while 267 trimmed existing stakes and 342 added.
The largest buyer was Point72 Asset Management, adding an estimated $427M. The largest seller was BlackRock, cutting an estimated $206M.
- 869 institutional investors held Biogen (BIIB) as of Q2 2025, down from 887 in Q1 2025.
- Funds reported $16.3B of Biogen stock for Q2 2025, down 8.1% quarter-over-quarter.
- 94 funds opened new Biogen positions in Q2 2025 and 102 closed out, a net change of -8 holders.
- The largest Biogen buyer in Q2 2025 was Point72 Asset Management, an estimated $427M added.
- The largest Biogen seller in Q2 2025 was BlackRock, an estimated $206M sold.
Based on aggregated 13F filings for Q2 2025.