Primecap Management Co/Ca/ - Sep 30, 2025 SCHEDULE 13G/A Report for Biogen Inc. COM (BIIB)

Filing Manager: PRIMECAP MANAGEMENT CO/CA/
Reporting Manager: PRIMECAP MANAGEMENT CO/CA/
Security: Biogen Inc. COM
Symbol: BIIB
Shares outstanding: 147M shares
Disclosed Ownership: 15M shares
Ownership: 10.2%
Form type: SCHEDULE 13G/A
Date filed: 11/13/2025, 08:28 PM
Date of event: Sep 30, 2025
SEC: View on sec.gov

Reporting Managers (1)

Name	Ownership	Shares Owned	sole voting power	shared voting power	Signature	Title	CIK
PRIMECAP MANAGEMENT CO/CA/	10.2%	15M	14.9M	0	Jorge A. Rodriguez	Deputy Chief Compliance Officer