Biogen Inc. SEC filings BIIB
Biogen Inc. has 1,001 filings in SEC EDGAR's recent list, going back to Oct 2, 2014. Its latest annual report, Form ARS, was filed on Apr 28, 2026 for the period ended Dec 31, 2025. The latest quarterly report (Form 10-Q) was filed on Oct 28, 2026, covering the quarter ended Sep 30, 2026. The most recent current report (Form 8-K) was filed on Oct 28, 2026 (results of operations). The company's fiscal year ends on December 31.
| Form | Description | Filed | Period |
|---|---|---|---|
| 4 | Insider transaction | Nov 2, 2026 | Oct 30, 2026 |
| 4 | Insider transaction | Oct 5, 2026 | Oct 1, 2026 |
| 4 | Insider transaction | Sep 3, 2026 | Sep 1, 2026 |
| 3 | Initial insider ownership | Aug 12, 2026 | Aug 3, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Aug 6, 2026 | — |
| 4 | Insider transaction | Aug 5, 2026 | Aug 3, 2026 |
| 144 | Notice of proposed sale | Aug 4, 2026 | — |
| 144 | Notice of proposed sale | Aug 3, 2026 | — |
| 4 | Insider transaction | Jun 11, 2026 | Jun 9, 2026 |
| 4 | Insider transaction | Jun 11, 2026 | Jun 9, 2026 |
| 4 | Insider transaction | Jun 11, 2026 | Jun 9, 2026 |
| 4 | Insider transaction | Jun 11, 2026 | Jun 9, 2026 |
| 4 | Insider transaction | Jun 11, 2026 | Jun 9, 2026 |
| 4 | Insider transaction | Jun 11, 2026 | Jun 9, 2026 |
| 4 | Insider transaction | Jun 11, 2026 | Jun 9, 2026 |
| 4 | Insider transaction | Jun 11, 2026 | Jun 9, 2026 |
| 4 | Insider transaction | Jun 11, 2026 | Jun 9, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jun 5, 2026 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | May 14, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | May 6, 2026 | — |
| 4 | Insider transaction | May 5, 2026 | May 1, 2026 |
| SCHEDULE 13G | Ownership over 5% (passive) | Apr 29, 2026 | — |
| 3 | Initial insider ownership | Apr 6, 2026 | Mar 31, 2026 |
| SCHEDULE 13D | Ownership over 5% (active) | Apr 6, 2026 | — |
| 4 | Insider transaction | Apr 3, 2026 | Apr 1, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Mar 26, 2026 | — |
| 4 | Insider transaction | Feb 17, 2026 | Feb 13, 2026 |
| 4 | Insider transaction | Feb 17, 2026 | Feb 13, 2026 |
| 4 | Insider transaction | Feb 17, 2026 | Feb 12, 2026 |
| 4 | Insider transaction | Feb 17, 2026 | Feb 13, 2026 |
| 4 | Insider transaction | Feb 17, 2026 | Feb 13, 2026 |
| 4 | Insider transaction | Feb 17, 2026 | Feb 13, 2026 |
| 4 | Insider transaction | Feb 17, 2026 | Feb 13, 2026 |
| 4 | Insider transaction | Feb 17, 2026 | Feb 13, 2026 |
| 4 | Insider transaction | Feb 17, 2026 | Feb 13, 2026 |
| 4 | Insider transaction | Feb 17, 2026 | Feb 13, 2026 |
| 4 | Insider transaction | Feb 10, 2026 | Feb 6, 2026 |
| 4 | Insider transaction | Feb 10, 2026 | Feb 6, 2026 |
| 4 | Insider transaction | Feb 10, 2026 | Feb 6, 2026 |
| 4 | Insider transaction | Feb 10, 2026 | Feb 6, 2026 |
| 4 | Insider transaction | Feb 10, 2026 | Feb 6, 2026 |
| 4 | Insider transaction | Feb 10, 2026 | Feb 6, 2026 |
| 4 | Insider transaction | Feb 10, 2026 | Feb 6, 2026 |
| 4 | Insider transaction | Feb 10, 2026 | Feb 6, 2026 |
| 4 | Insider transaction | Feb 10, 2026 | Feb 6, 2026 |
| 4 | Insider transaction | Feb 10, 2026 | Feb 6, 2026 |
| 144 | Notice of proposed sale | Feb 9, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Feb 5, 2026 | — |
| 4 | Insider transaction | Feb 3, 2026 | Jan 30, 2026 |
| 144 | Notice of proposed sale | Feb 2, 2026 | — |
| 4 | Insider transaction | Dec 3, 2025 | Dec 1, 2025 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Nov 13, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Nov 10, 2025 | — |
| 4 | Insider transaction | Nov 4, 2025 | Oct 31, 2025 |
| 4 | Insider transaction | Oct 6, 2025 | Oct 2, 2025 |
| 4 | Insider transaction | Sep 2, 2025 | Aug 29, 2025 |
| 144 | Notice of proposed sale | Sep 2, 2025 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Jul 30, 2025 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Jul 21, 2025 | — |
| 4 | Insider transaction | Jul 16, 2025 | Jul 8, 2025 |
| 144 | Notice of proposed sale | Jul 8, 2025 | — |
| 4 | Insider transaction | Jun 18, 2025 | Jun 17, 2025 |
| 4 | Insider transaction | Jun 18, 2025 | Jun 17, 2025 |
| 4 | Insider transaction | Jun 18, 2025 | Jun 17, 2025 |
| 4 | Insider transaction | Jun 18, 2025 | Jun 17, 2025 |
| 4 | Insider transaction | Jun 18, 2025 | Jun 17, 2025 |
| 4 | Insider transaction | Jun 18, 2025 | Jun 17, 2025 |
| 4 | Insider transaction | Jun 18, 2025 | Jun 17, 2025 |
| 4 | Insider transaction | Jun 18, 2025 | Jun 17, 2025 |
| 4 | Insider transaction | Jun 18, 2025 | Jun 17, 2025 |
| 4 | Insider transaction | Jun 18, 2025 | Jun 17, 2025 |
| 4 | Insider transaction | May 20, 2025 | May 19, 2025 |
| 144 | Notice of proposed sale | May 19, 2025 | — |
| 4 | Insider transaction | May 5, 2025 | May 1, 2025 |
| 4 | Insider transaction | May 5, 2025 | May 2, 2025 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Apr 17, 2025 | — |
| 4 | Insider transaction | Apr 3, 2025 | Apr 1, 2025 |
| 4 | Insider transaction | Mar 10, 2025 | Mar 7, 2025 |
| 3 | Initial insider ownership | Mar 10, 2025 | Mar 1, 2025 |
| 144 | Notice of proposed sale | Mar 7, 2025 | — |
| 4 | Insider transaction | Feb 12, 2025 | Feb 10, 2025 |
| 4 | Insider transaction | Feb 12, 2025 | Feb 10, 2025 |
| 4 | Insider transaction | Feb 12, 2025 | Feb 10, 2025 |
| 4 | Insider transaction | Feb 12, 2025 | Feb 10, 2025 |
| 4 | Insider transaction | Feb 12, 2025 | Feb 10, 2025 |
| 4 | Insider transaction | Feb 12, 2025 | Feb 10, 2025 |
| 4 | Insider transaction | Feb 12, 2025 | Feb 10, 2025 |
| 4 | Insider transaction | Feb 11, 2025 | Feb 7, 2025 |
| 4 | Insider transaction | Feb 10, 2025 | Feb 7, 2025 |
| 4 | Insider transaction | Feb 10, 2025 | Feb 6, 2025 |
| 4 | Insider transaction | Feb 10, 2025 | Feb 6, 2025 |
| 4 | Insider transaction | Feb 10, 2025 | Feb 6, 2025 |
| 4 | Insider transaction | Feb 10, 2025 | Feb 6, 2025 |
| 4 | Insider transaction | Feb 10, 2025 | Feb 6, 2025 |
| 4 | Insider transaction | Feb 10, 2025 | Feb 6, 2025 |
| 4 | Insider transaction | Feb 10, 2025 | Feb 6, 2025 |
| 4 | Insider transaction | Feb 10, 2025 | Feb 6, 2025 |
| 4 | Insider transaction | Feb 10, 2025 | Feb 6, 2025 |
| 4 | Insider transaction | Feb 3, 2025 | Jan 31, 2025 |
| SCHEDULE 13D | Ownership over 5% (active) | Jan 10, 2025 | — |
| 3 | Initial insider ownership | Jan 7, 2025 | Jan 1, 2025 |
| 4 | Insider transaction | Dec 9, 2024 | Dec 6, 2024 |
| 4 | Insider transaction | Dec 9, 2024 | Dec 6, 2024 |
| 144 | Notice of proposed sale | Dec 9, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Nov 12, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Nov 7, 2024 | — |
| 4 | Insider transaction | Nov 7, 2024 | Nov 5, 2024 |
| 4 | Insider transaction | Nov 4, 2024 | Nov 1, 2024 |
| SC 13G/A | Amended ownership over 5% (passive) | Nov 4, 2024 | — |
| SC 13G | Ownership over 5% (passive) | Oct 16, 2024 | — |
| 3 | Initial insider ownership | Oct 7, 2024 | Oct 1, 2024 |
| 4 | Insider transaction | Sep 5, 2024 | Aug 30, 2024 |
| 144 | Notice of proposed sale | Sep 3, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Aug 16, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Aug 7, 2024 | — |
| 4 | Insider transaction | Jun 25, 2024 | Jun 21, 2024 |
| 4 | Insider transaction | Jun 25, 2024 | Jun 21, 2024 |
| 4 | Insider transaction | Jun 25, 2024 | Jun 21, 2024 |
| 4 | Insider transaction | Jun 25, 2024 | Jun 21, 2024 |
| 4 | Insider transaction | Jun 25, 2024 | Jun 21, 2024 |
| 4 | Insider transaction | Jun 25, 2024 | Jun 21, 2024 |
| 4 | Insider transaction | Jun 25, 2024 | Jun 21, 2024 |
| 4 | Insider transaction | Jun 25, 2024 | Jun 21, 2024 |
| 4 | Insider transaction | May 3, 2024 | May 1, 2024 |
| 4 | Insider transaction | Apr 3, 2024 | Apr 2, 2024 |
| 4 | Insider transaction | Apr 3, 2024 | Apr 1, 2024 |
| 144 | Notice of proposed sale | Apr 2, 2024 | — |
| 4 | Insider transaction | Feb 26, 2024 | Feb 22, 2024 |
| 144 | Notice of proposed sale | Feb 22, 2024 | — |
| 4 | Insider transaction | Feb 21, 2024 | Feb 16, 2024 |
| 4 | Insider transaction | Feb 21, 2024 | Feb 16, 2024 |
| 4 | Insider transaction | Feb 21, 2024 | Feb 16, 2024 |
| 4 | Insider transaction | Feb 21, 2024 | Feb 16, 2024 |
| 4 | Insider transaction | Feb 21, 2024 | Feb 16, 2024 |
| 4 | Insider transaction | Feb 21, 2024 | Feb 16, 2024 |
| 4 | Insider transaction | Feb 21, 2024 | Feb 16, 2024 |
| 144 | Notice of proposed sale | Feb 21, 2024 | — |
| 4 | Insider transaction | Feb 20, 2024 | Feb 15, 2024 |
| 4 | Insider transaction | Feb 13, 2024 | Feb 9, 2024 |
| 4 | Insider transaction | Feb 13, 2024 | Feb 9, 2024 |
| 4 | Insider transaction | Feb 13, 2024 | Feb 9, 2024 |
| 4 | Insider transaction | Feb 13, 2024 | Feb 9, 2024 |
| 4 | Insider transaction | Feb 13, 2024 | Feb 9, 2024 |
| 4 | Insider transaction | Feb 13, 2024 | Feb 9, 2024 |
| 4 | Insider transaction | Feb 13, 2024 | Feb 9, 2024 |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 12, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 12, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 12, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 12, 2024 | — |
| 144 | Notice of proposed sale | Feb 12, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 12, 2024 | — |
| 4 | Insider transaction | Feb 9, 2024 | Feb 7, 2024 |
| 4 | Insider transaction | Feb 9, 2024 | Feb 7, 2024 |
| 4 | Insider transaction | Feb 9, 2024 | Feb 7, 2024 |
| 4 | Insider transaction | Feb 9, 2024 | Feb 7, 2024 |
| 4 | Insider transaction | Feb 9, 2024 | Feb 7, 2024 |
| 4 | Insider transaction | Feb 9, 2024 | Feb 7, 2024 |
| 4 | Insider transaction | Feb 9, 2024 | Feb 7, 2024 |
| 4 | Insider transaction | Feb 9, 2024 | Feb 7, 2024 |
| 4 | Insider transaction | Feb 9, 2024 | Feb 7, 2024 |
| 4 | Insider transaction | Feb 9, 2024 | Feb 7, 2024 |
| 4 | Insider transaction | Feb 5, 2024 | Feb 1, 2024 |
| 144 | Notice of proposed sale | Feb 2, 2024 | — |
| 4 | Insider transaction | Jan 31, 2024 | Jan 29, 2024 |
| 4 | Insider transaction | Jan 31, 2024 | Jan 29, 2024 |
| 4 | Insider transaction | Jan 31, 2024 | Jan 29, 2024 |
| 4 | Insider transaction | Jan 31, 2024 | Jan 29, 2024 |
| 4 | Insider transaction | Jan 31, 2024 | Jan 29, 2024 |
| 4 | Insider transaction | Jan 31, 2024 | Jan 29, 2024 |
| 4 | Insider transaction | Jan 31, 2024 | Jan 29, 2024 |
| SC 13G/A | Amended ownership over 5% (passive) | Jan 24, 2024 | — |
| 3 | Initial insider ownership | Jan 9, 2024 | Jan 1, 2024 |
| 4 | Insider transaction | Dec 12, 2023 | Dec 8, 2023 |
| 4 | Insider transaction | Dec 12, 2023 | Dec 8, 2023 |
| 144 | Notice of proposed sale | Dec 11, 2023 | — |
| 4 | Insider transaction | Nov 3, 2023 | Nov 1, 2023 |
| 3 | Initial insider ownership | Oct 12, 2023 | Oct 2, 2023 |
| 4 | Insider transaction | Sep 28, 2023 | Sep 26, 2023 |
| SC 13D/A | Amended ownership over 5% (active) | Sep 28, 2023 | — |
| 4 | Insider transaction | Sep 6, 2023 | Sep 1, 2023 |
| 4 | Insider transaction | Sep 6, 2023 | Sep 1, 2023 |
| 144 | Notice of proposed sale | Sep 5, 2023 | — |
| SC 13D | Ownership over 5% (active) | Aug 7, 2023 | — |
| 3 | Initial insider ownership | Aug 7, 2023 | Jul 28, 2023 |
| 4 | Insider transaction | Jul 5, 2023 | Jun 30, 2023 |
| 4 | Insider transaction | Jul 5, 2023 | Jun 30, 2023 |
| 4 | Insider transaction | Jul 5, 2023 | Jun 30, 2023 |
| 144 | Notice of proposed sale | Jul 3, 2023 | — |
| 4 | Insider transaction | Jun 28, 2023 | Jun 26, 2023 |
| 4 | Insider transaction | Jun 28, 2023 | Jun 26, 2023 |
| 4 | Insider transaction | Jun 28, 2023 | Jun 26, 2023 |
| 4 | Insider transaction | Jun 28, 2023 | Jun 26, 2023 |
| 3 | Initial insider ownership | Jun 28, 2023 | Jun 26, 2023 |
| 4 | Insider transaction | Jun 28, 2023 | Jun 26, 2023 |
| 4 | Insider transaction | Jun 28, 2023 | Jun 26, 2023 |
| 4 | Insider transaction | Jun 28, 2023 | Jun 26, 2023 |
| 4 | Insider transaction | May 2, 2023 | May 1, 2023 |
| 4 | Insider transaction | May 2, 2023 | Apr 28, 2023 |
| 144 | Notice of proposed sale | Apr 28, 2023 | — |
| 3 | Initial insider ownership | Apr 25, 2023 | Apr 17, 2023 |
Showing 200 filings, the most recent 200. Main filings leave out insider and ownership forms such as Form 4; choose a type above to see them. Each form opens on SEC.gov. Older filings are on SEC EDGAR.
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Company profile
- Industry
- Biological Products, (No Diagnostic Substances) (SIC 2836)
- Listed as
- BIIB (Nasdaq)
- Fiscal year ends
- December 31
- Incorporated in
- DE
- Headquarters
- Cambridge, MA
- SEC filer status
- Large accelerated filer
- SEC CIK
- 875045
- Former names
- BIOGEN IDEC INC. (until Mar 20, 2015); BIOGEN IDEC INC (until Apr 25, 2007); IDEC PHARMACEUTICALS CORP / DE (until Nov 12, 2003); IDEC PHARMACEUTICALS CORP / CA (until Feb 14, 1997)
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All 182 Biological Products, (No Diagnostic Substances) companies
Source: SEC EDGAR filings. This is company-reported data, not investment advice.