Biogen
BIIB
1,011 hedge funds and large institutions have $24.7B invested in Biogen in 2026 Q1 according to their latest regulatory filings, with 136 funds opening new positions, 402 increasing their positions, 290 reducing their positions, and 107 closing their positions.
39% more repeat investments, than reductions
Existing positions increased: 402 | Existing positions reduced: 290
27% more first-time investments, than exits
New positions opened: 136 | Existing positions closed: 107
1% more funds holding
Funds holding: 1,001 → 1,011 (+10)
1% more capital invested
Capital invested by funds: $24.6B → $24.7B (+$148M)
10% less call options, than puts
Call options by funds: $324M | Put options by funds: $360M
3.29% less ownership
Funds ownership: 95.25% → 91.95% (-3.3%)
13% less funds holding in top 10
Funds holding in top 10: 8 → 7 (-1)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Fidelity Investments
Boston,
Massachusetts
|
+$623M |
| 2 |
BlackRock
New York
|
+$214M |
| 3 |
AQR Capital Management
Greenwich,
Connecticut
|
+$72.8M |
| 4 |
AIM
Artemis Investment Management
Edinburgh,
United Kingdom
|
+$63.5M |
| 5 |
SI
Sofinnova Investments
Menlo Park,
California
|
+$42.3M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Point72 Asset Management
Stamford,
Connecticut
|
-$369M |
| 2 |
Millennium Management
New York
|
-$190M |
| 3 |
Barclays
London,
United Kingdom
|
-$139M |
| 4 |
Wellington Management Group
Boston,
Massachusetts
|
-$109M |
| 5 |
Susquehanna International Group
Bala Cynwyd,
Pennsylvania
|
-$96.1M |
BIIB Hedge Fund Activity: Q1 2026 in Review
1,011 of the 8,190 institutional investors tracked by Wall St. Rank reported a position in Biogen (BIIB) for Q1 2026, worth a combined $24.7B — up 0.6% from $24.6B a quarter earlier.
Buyers outnumbered sellers: 136 funds opened new BIIB positions and 107 closed out — a net gain of 29 holders — while 402 added to existing stakes and 290 trimmed.
The largest buyer was Fidelity Investments, adding an estimated $623M. The largest seller was Point72 Asset Management, cutting an estimated $369M.
- 1,011 institutional investors held Biogen (BIIB) as of Q1 2026, up from 1,001 in Q4 2025.
- Funds reported $24.7B of Biogen stock for Q1 2026, up 0.6% quarter-over-quarter.
- 136 funds opened new Biogen positions in Q1 2026 and 107 closed out, a net change of +29 holders.
- The largest Biogen buyer in Q1 2026 was Fidelity Investments, an estimated $623M added.
- The largest Biogen seller in Q1 2026 was Point72 Asset Management, an estimated $369M sold.
Based on aggregated 13F filings for Q1 2026.