Biogen Inc.
Ownership
Ownership Structure
Who owns Biogen Inc. (BIIB)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 99.6% of the shares are freely tradable; institutional investors hold 96.4%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| FMR Inc | 12.33 | 18,217,239 | +42.2 | 06/30/2026 |
| BlackRock Inc | 10.82 | 15,985,736 | +0.1 | 06/30/2026 |
| PRIMECAP Management Company | 10.26 | 15,154,606 | +2.7 | 06/30/2026 |
| Vanguard Capital Management, LLC | 6.53 | 9,651,117 | +1.2 | 06/30/2026 |
| State Street Corp | 4.97 | 7,344,327 | +2.5 | 06/30/2026 |
| Vanguard Portfolio Management, LLC | 4.47 | 6,604,936 | +1.1 | 06/30/2026 |
| Geode Capital Management, LLC | 3.01 | 4,449,295 | +2.5 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Vanguard PRIMECAP Inv | 5.66 | 8,359,880 | +0.0 | 06/30/2026 |
| Fidelity Contrafund | 3.26 | 4,817,040 | -3.4 | 08/31/2026 |
| Vanguard MStar Total Stk Mkt Idx Invest | 3.17 | 4,683,142 | -0.2 | 09/30/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Minor Lloyd | Director | 2,689 | 669,561 $ | Aug 4, 2026 | direct |
| Godbout Sean | Chief Accounting Officer | 1,459 | 363,287 $ | Oct 2, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Oct 2, 2026 | Godbout Sean | Chief Accounting Officer | Other | 8 | 219.88 | 1,759 |
| Oct 2, 2026 | Godbout Sean | Chief Accounting Officer | Other | 27 | 0.00 | – |
| Aug 4, 2026 | Minor Lloyd | Director | Sell | 593 | 200.96 | 119,169 |
| Aug 3, 2026 | Minor Lloyd | Director | Sell | 593 | 203.34 | 120,581 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: November 2, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.