Biogen Inc.
BIIB- Exchange
- Nasdaq
- Industry
- Biological Products, (No Diagnostic Substances)
- SEC CIK
- 0000875045
In the last 90 days, Biogen Inc. insiders filed 0 open-market purchases and 1 sale; 1,046 institutions reported holding it in 13F filings for Q2 2026, worth $30.7B in total; no superinvestor holds it.
Holders of 5% or more of BIIB
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Biogen Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| Primecap Management Co | 13G/A | 10.20%15.0M shares | – | Nov 13, 20251 filing | Nov 13, 2025 | SEC |
| BlackRock, Inc. | 13G/A | 8.50%12.5M shares | – | Apr 17, 20251 filing | Apr 17, 2025 | SEC |
| State Street Corp | 13G | 5.00%7.32M shares | New | Nov 10, 20251 filing | Nov 10, 2025 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
4 Schedule 13D and 13G filings on Biogen Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Mar 26, 20264:09 PM ET | Vanguard Group Inc | 13G/A | 0.00%0 shares | –Below 5% | Mar 13, 2026 | SEC |
| Nov 13, 20258:28 PM ET | Primecap Management Co | 13G/A | 10.20%15.0M shares | – | Sep 30, 2025 | SEC |
| Nov 10, 20258:15 AM ET | State Street Corp | 13G | 5.00%7.32M shares | New | Sep 30, 2025 | SEC |
| Apr 17, 20259:35 AM ET | BlackRock, Inc. | 13G/A | 8.50%12.5M shares | – | Mar 31, 2025 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Biogen Inc. shares.
No Form 144 notices for Biogen Inc. are on file.