BIOGEN INC. (BIIB) · Insider Trading (Form 4) SEC Filing

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-04-01 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: BIOGEN INC. (BIIB) CIK: 0000875045 --- Reporting Owner --- Name: Godbout Sean CIK: 0002057736 Role: Officer (Chief Accounting Officer) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-04-01 | Code: M (Exercise of derivative) Shares: +181 | Price: $0.00 Shares Owned After: 1,395.6667 | Ownership: D (Direct) [Transaction #2] Security: Common Stock Date: 2026-04-01 | Code: F (Payment of exercise/tax) Shares: -54 | Price: $183.78 Total Value: $9,924.12 Shares Owned After: 1,341.6667 | Ownership: D (Direct) --- Derivative Transactions --- [Transaction #1] Security: Restricted Stock Unit Date: 2026-04-01 | Code: M (Exercise of derivative) Shares: -181 | Price: $0.00 Exercisable: N/A | Expires: 2028-04-01 Shares Owned After: 364 | Ownership: D (Direct) Footnotes: [F1] The restricted stock units vest in three equal yearly installments beginning on the first anniversary of the grant date of April 1, 2025. --- Footnotes (Complete Index) --- F1: The restricted stock units vest in three equal yearly installments beginning on the first anniversary of the grant date of April 1, 2025. --- Signature --- /s/ /s/ Wendell Taylor, attorney-in-fact for Mr. Godbout (2026-04-03)