BIIB BIOGEN INC
FollowStock (common), issuer CIK 875045
1,014 managers (1,047 13F filers) reported a position in BIIB shares at 2026-06-30, 142,281,347 shares in all. 112 filers opened a position and 82 filers sold out during the quarter.
- Managers
- 1,014
- 13F filers
- 1,047
- New
- 112
- Added
- 427
- Reduced
- 297
- Sold out
- 82
- Shares held by filers
- 142,281,347
Shares held by filers adds up every 13F filer's report, so a share reported by a parent and by its subsidiary counts twice (H9). Managers counts each filer group once.
13D and 13G filers
No 13D or 13G on this security in the data. Structured 13D/G data starts 2024-12-18.
Insider trades
No Form 4 transaction on this security in the data.
13F holders, Q2 2026
Filers in the available 13F reports with a share position at 2026-06-30, filer groups collapsed to one row (method), largest first. Options and principal amounts are left out. A group row states no % of portfolio, since each member reports its own portfolio: the members' percents are listed under it. A value about 1,000 times or 1/1,000 of the price other filers imply is shown as filed but neither ranks the row nor enters a sum.