Biogen Inc. (BIIB) Shareholders & Insider Trades
Biogen shareholders at a glance
The largest holder of Biogen stock is Fidelity Management & Research Co. LLC, with 18.2 million shares (12.33% of the company), worth about $3.95 billion as of September 25, 2026. The 10 largest holders together own 56.0%.
In Q2 2026, 1,113 institutional holdings reports listed shares worth $33.40 billion.
Insiders reported 58 transactions in the last two years: 7 sales worth $2.85 million and 2 purchases. The newest one on file is from May 1, 2026 (Keeney Adam James, Officer).
Major holders as of September 25, 2026; quarterly totals from institutional holdings reports (latest Q2 2026); insider transactions on file through May 1, 2026.
Biogen Inc.
Shareholders Summary
2026Q2
Ownership by Type
Geographic Distribution
Largest Biogen shareholders
| Holder | Shares | % of company | Value |
|---|---|---|---|
| Fidelity Management & Research Co. LLC | 18.2 million | 12.33% | $3.9B |
| PRIMECAP Management Co. | 15.2 million | 10.26% | $3.3B |
| BlackRock Advisors LLC | 11.6 million | 7.85% | $2.5B |
| Vanguard Capital Management LLC | 9.7 million | 6.53% | $2.1B |
| State Street Corporation | 7.3 million | 4.97% | $1.6B |
| Vanguard Portfolio Management LLC | 6.6 million | 4.47% | $1.4B |
| Geode Capital Management LLC | 4.4 million | 3.01% | $964.0M |
| BlackRock Life Ltd. | 4.1 million | 2.76% | $883.0M |
| Wellington Trust Co., NA | 3.1 million | 2.11% | $675.0M |
| Norges Bank (13F) | 2.6 million | 1.75% | $559.0M |
As of September 25, 2026.
Biogen institutional holdings by quarter
| Quarter | Reports | Shares | Value |
|---|---|---|---|
| Q2 2026 | 1,113 | – | $33.4B |
| Q1 2026 | 1,068 | 135.0 million | $24.7B |
| Q4 2025 | 1,066 | 141.0 million | $24.8B |
| Q3 2025 | 980 | 133.0 million | $18.7B |
| Q2 2025 | 928 | 132.0 million | $16.6B |
| Q1 2025 | 943 | 130.0 million | $17.8B |
| Q4 2024 | 949 | 133.0 million | $20.3B |
| Q3 2024 | 996 | 136.0 million | $26.1B |
Shares and value held by institutions that file quarterly holdings reports (options not included).
Biogen insider trades
| Insider | Date | Title | Transaction | Value |
|---|---|---|---|---|
| Keeney Adam James | May 1, 2026 | Officer | -- | – |
| Godbout Sean | Apr 1, 2026 | Officer | -- | – |
| Murphy Nicole | Feb 12, 2026 | Officer | Purchase at price 195.04 per share. | $585 |
| Singhal Priya | Feb 9, 2026 | Officer | Sale at price 199.83 per share. | $531,548 |
| Alexander Susan H | Feb 6, 2026 | Officer | -- | – |
| Izzar Rachid | Feb 6, 2026 | Officer | -- | – |
| Murphy Nicole | Feb 6, 2026 | Officer | -- | – |
| Keeney Adam James | Feb 6, 2026 | Officer | -- | – |
| Grogan Jane | Feb 6, 2026 | Officer | -- | – |
| Godbout Sean | Feb 6, 2026 | Officer | -- | – |
| Singhal Priya | Feb 6, 2026 | Officer | -- | – |
| Viehbacher Christopher | Feb 6, 2026 | Chief Executive Officer | -- | – |
Newest 12 of 58 insider transactions in the last two years.
Questions and answers
Who owns the most Biogen stock?
Fidelity Management & Research Co. LLC, with 12.33% of the company (as of September 25, 2026). Next: PRIMECAP Management Co. (10.26%) and BlackRock Advisors LLC (7.85%).
How many institutions own Biogen stock?
1,113 institutional holdings reports listed Biogen shares in Q2 2026 worth $33.40 billion.
Are Biogen insiders buying or selling the stock?
In the last two years insiders reported 7 sales and 2 purchases (58 transactions in all); the newest on file is from May 1, 2026.
