BIOGEN INC. - Director's Dealing 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN INC. (BIIB)
CIK: 0000875045
Period of Report: 2026-02-06

Reporting Person: Grogan Jane (Head of Research)

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-02-06	Common Stock	M	1385	—	Acquired	3176	Direct
2026-02-06	Common Stock	F	407	$201.18	Disposed	2769	Direct
2026-02-06	Common Stock	M	1873	—	Acquired	4642	Direct
2026-02-06	Common Stock	F	584	$201.18	Disposed	4058	Direct

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2026-02-06	Restricted Stock Unit	$0	M	1385	Disposed	2027-02-07	Common Stock (1385)	Direct
2026-02-06	Restricted Stock Unit	$0	M	1873	Disposed	2028-02-06	Common Stock (1873)	Direct

F1: The restricted stock units vest in three (3) equal annual installments, commencing one year after the grant date of 02/07/2024.

F2: The restricted stock units vest in three equal yearly installments beginning on the first anniversary of the grant date of February 6, 2025.