BIOGEN INC. — Director's Dealing 2026

Feb 10, 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

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

Reporting Person: Viehbacher Christopher (Director, President and CEO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-02-06	Common Stock	M	9008	—	Acquired	25451	Direct
2026-02-06	Common Stock	F	4356	$201.18	Disposed	21095	Direct
2026-02-06	Common Stock	M	15453	—	Acquired	36548	Direct
2026-02-06	Common Stock	F	6624	$201.18	Disposed	29924	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2026-02-06	Restricted Stock Unit	$0	M	9008	Disposed	2027-02-07	Common Stock (9008)	Direct
2026-02-06	Restricted Stock Unit	$0	M	15453	Disposed	2028-02-06	Common Stock (15453)	Direct

Footnotes

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.