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

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-05-01 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: BIOGEN INC. (BIIB) CIK: 0000875045 --- Reporting Owner --- Name: Keeney Adam CIK: 0001973607 Role: Officer (Head of Corporate Development) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-05-01 | Code: M (Exercise of derivative) Shares: +939 | Price: $0.00 Shares Owned After: 6,820 | Ownership: D (Direct) [Transaction #2] Security: Common Stock Date: 2026-05-01 | Code: F (Payment of exercise/tax) Shares: -455 | Price: $187.06 Total Value: $85,112.30 Shares Owned After: 6,365 | Ownership: D (Direct) --- Derivative Transactions --- [Transaction #1] Security: Restricted Stock Unit Date: 2026-05-01 | Code: M (Exercise of derivative) Shares: -939 | Price: $0.00 Exercisable: N/A | Expires: 2026-05-01 Shares Owned After: 0 | 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 May 1, 2023. --- Footnotes (Complete Index) --- F1: The restricted stock units vest in three equal yearly installments beginning on the first anniversary of the grant date of May 1, 2023. --- Signature --- /s/ /s/ Wendell Taylor, attorney-in-fact for Mr. Keeney (2026-05-05)