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 |
| 10-Q | Quarterly report | Oct 28, 2026 | Sep 30, 2026 |
| 8-K |
Current report
Results of operations
|
Oct 28, 2026 | Oct 28, 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 | — |
| 10-Q | Quarterly report | Jul 29, 2026 | Jun 30, 2026 |
| 8-K |
Current report
Results of operations
|
Jul 29, 2026 | Jul 29, 2026 |
| 8-K |
Current report
Results of operations
|
Jul 1, 2026 | Jul 1, 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 |
| 8-K |
Current report
Shareholder vote results
|
Jun 10, 2026 | Jun 9, 2026 |
| 8-K/A | Amended current report | Jun 10, 2026 | May 14, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jun 5, 2026 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | May 14, 2026 | — |
| 8-K |
Current report
Material agreement, Acquisition or sale of assets, New debt, Regulation FD disclosure
|
May 14, 2026 | May 14, 2026 |
| SC TO-T/A | Filing | May 14, 2026 | — |
| SC TO-T/A | Amendment no. 2 | May 12, 2026 | — |
| SC TO-T/A | Amendment no. 1 | May 6, 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 | — |
| 10-Q | Quarterly report | Apr 29, 2026 | Mar 31, 2026 |
| 8-K |
Current report
Results of operations
|
Apr 29, 2026 | Apr 29, 2026 |
| ARS | Annual report to shareholders | Apr 28, 2026 | Dec 31, 2025 |
| DEFA14A | Additional proxy material | Apr 28, 2026 | — |
| DEF 14A | Proxy statement | Apr 28, 2026 | Jun 9, 2026 |
| SC TO-T | Filing | Apr 14, 2026 | — |
| SC TO-C | Schedule to | Apr 7, 2026 | — |
| 3 | Initial insider ownership | Apr 6, 2026 | Mar 31, 2026 |
| SCHEDULE 13D | Ownership over 5% (active) | Apr 6, 2026 | — |
| 8-K |
Current report
Results of operations
|
Apr 6, 2026 | Apr 6, 2026 |
| SC TO-C | Schedule to | Apr 3, 2026 | — |
| 4 | Insider transaction | Apr 3, 2026 | Apr 1, 2026 |
| SC TO-C | Filing | Mar 31, 2026 | — |
| 8-K |
Current report
Material agreement, Other events
|
Mar 31, 2026 | Mar 31, 2026 |
| SC TO-C | Schedule to | Mar 31, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Mar 26, 2026 | — |
| 8-K |
Current report
Officer or director change
|
Mar 11, 2026 | Mar 11, 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 |
| 8-K |
Current report
Officer or director change, Other events
|
Feb 11, 2026 | Feb 11, 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 | — |
| 10-K | Annual report | Feb 6, 2026 | Dec 31, 2025 |
| 8-K |
Current report
Results of operations
|
Feb 6, 2026 | Feb 6, 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 | — |
| 8-K |
Current report
Results of operations
|
Jan 14, 2026 | Jan 13, 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 |
| 10-Q | Quarterly report | Oct 30, 2025 | Sep 30, 2025 |
| 8-K |
Current report
Results of operations
|
Oct 30, 2025 | Oct 30, 2025 |
| 8-K |
Current report
Results of operations
|
Oct 14, 2025 | Oct 14, 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 | — |
| 8-K |
Current report
Results of operations
|
Jul 31, 2025 | Jul 31, 2025 |
| 10-Q | Quarterly report | Jul 31, 2025 | Jun 30, 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 | — |
| 8-K |
Current report
Results of operations
|
Jul 7, 2025 | Jul 7, 2025 |
| 8-K |
Current report
Shareholder vote results
|
Jun 23, 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 | Jun 18, 2025 | Jun 17, 2025 |
| DEFA14A | Additional proxy material | Jun 2, 2025 | — |
| 4 | Insider transaction | May 20, 2025 | May 19, 2025 |
| 144 | Notice of proposed sale | May 19, 2025 | — |
| 8-K |
Current report
Other events
|
May 12, 2025 | May 6, 2025 |
| 424B2 | Prospectus | May 8, 2025 | — |
| FWP | Free writing prospectus | May 6, 2025 | — |
| 424B2 | Prospectus | May 6, 2025 | — |
| 4 | Insider transaction | May 5, 2025 | May 1, 2025 |
| 4 | Insider transaction | May 5, 2025 | May 2, 2025 |
| S-3ASR | Automatic shelf registration | May 1, 2025 | — |
| 10-Q | Quarterly report | May 1, 2025 | Mar 31, 2025 |
| 8-K |
Current report
Results of operations
|
May 1, 2025 | May 1, 2025 |
| ARS | Annual report to shareholders | Apr 28, 2025 | Dec 31, 2024 |
| DEFA14A | Additional proxy material | Apr 28, 2025 | — |
| DEF 14A | Proxy statement | Apr 28, 2025 | Jun 17, 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 |
| 10-K | Annual report | Feb 12, 2025 | Dec 31, 2024 |
| 8-K |
Current report
Results of operations
|
Feb 12, 2025 | Feb 12, 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 |
| 8-K |
Current report
Officer or director change
|
Jan 15, 2025 | Jan 13, 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 | — |
| 8-K |
Current report
Officer or director change, Regulation FD disclosure
|
Oct 30, 2024 | Oct 28, 2024 |
| 10-Q | Quarterly report | Oct 30, 2024 | Sep 30, 2024 |
| 8-K |
Current report
Results of operations
|
Oct 30, 2024 | Oct 30, 2024 |
| SC 13G | Ownership over 5% (passive) | Oct 16, 2024 | — |
| 3 | Initial insider ownership | Oct 7, 2024 | Oct 1, 2024 |
| 8-K |
Current report
Officer or director change
|
Sep 12, 2024 | Sep 11, 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 | — |
| 8-K |
Current report
Material agreement, Agreement ended, New debt
|
Aug 14, 2024 | Aug 12, 2024 |
| SC 13G/A | Amended ownership over 5% (passive) | Aug 7, 2024 | — |
| 10-Q | Quarterly report | Aug 1, 2024 | Jun 30, 2024 |
| 8-K |
Current report
Results of operations
|
Aug 1, 2024 | Aug 1, 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 |
| 8-K |
Current report
Bylaw or fiscal year change, Shareholder vote results
|
Jun 25, 2024 | Jun 20, 2024 |
| S-8 | Employee stock plan registration | Jun 20, 2024 | — |
| 4 | Insider transaction | May 3, 2024 | May 1, 2024 |
| ARS | Annual report to shareholders | Apr 26, 2024 | Dec 31, 2023 |
| DEFA14A | Additional proxy material | Apr 26, 2024 | — |
| DEF 14A | Proxy statement | Apr 26, 2024 | Jun 20, 2024 |
| 10-Q | Quarterly report | Apr 24, 2024 | Mar 31, 2024 |
| 8-K |
Current report
Results of operations
|
Apr 24, 2024 | Apr 24, 2024 |
| PRE 14A | Preliminary proxy statement | Apr 12, 2024 | Jun 20, 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 |
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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.