Biogen
BIIB
1,000 hedge funds and large institutions have $24.6B invested in Biogen in 2025 Q4 according to their latest regulatory filings, with 190 funds opening new positions, 322 increasing their positions, 295 reducing their positions, and 81 closing their positions.
167% more funds holding in top 10
Funds holding in top 10: 3 → 8 (+5)
135% more first-time investments, than exits
New positions opened: 190 | Existing positions closed: 81
58% more call options, than puts
Call options by funds: $715M | Put options by funds: $454M
33% more capital invested
Capital invested by funds: $18.5B → $24.6B (+$6.12B)
10% more funds holding
Funds holding: 907 → 1,000 (+93)
5.68% more ownership
Funds ownership: 89.57% → 95.24% (+5.7%)
9% more repeat investments, than reductions
Existing positions increased: 322 | Existing positions reduced: 295
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Fidelity Investments
Boston,
Massachusetts
|
+$1.33B |
| 2 |
Boston Partners
Boston,
Massachusetts
|
+$281M |
| 3 |
FAM
Fred Alger Management
New York
|
+$130M |
| 4 |
JP Morgan Chase
New York
|
+$96.2M |
| 5 |
HF
HRT Financial
New York
|
+$62.1M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Point72 Asset Management
Stamford,
Connecticut
|
-$173M |
| 2 |
Invesco
Atlanta,
Georgia
|
-$125M |
| 3 |
Wellington Management Group
Boston,
Massachusetts
|
-$114M |
| 4 |
Balyasny Asset Management
Chicago,
Illinois
|
-$102M |
| 5 |
Man Group
London,
United Kingdom
|
-$94.6M |
BIIB Hedge Fund Activity: Q4 2025 in Review
1,000 of the 8,284 institutional investors tracked by Wall St. Rank reported a position in Biogen (BIIB) for Q4 2025, worth a combined $24.6B — up 33% from $18.5B a quarter earlier.
Buyers outnumbered sellers: 190 funds opened new BIIB positions and 81 closed out — a net gain of 109 holders — while 322 added to existing stakes and 295 trimmed.
The largest buyer was Fidelity Investments, adding an estimated $1.33B. The largest seller was Point72 Asset Management, cutting an estimated $173M.
- 1,000 institutional investors held Biogen (BIIB) as of Q4 2025, up from 907 in Q3 2025.
- Funds reported $24.6B of Biogen stock for Q4 2025, up 33% quarter-over-quarter.
- 190 funds opened new Biogen positions in Q4 2025 and 81 closed out, a net change of +109 holders.
- The largest Biogen buyer in Q4 2025 was Fidelity Investments, an estimated $1.33B added.
- The largest Biogen seller in Q4 2025 was Point72 Asset Management, an estimated $173M sold.
Based on aggregated 13F filings for Q4 2025.