PRIMECAP MANAGEMENT CO/CA/ - 30 Sep 2025 SCHEDULE 13G/A Report for Biogen Inc. COM (BIIB)

Reporting Manager
PRIMECAP MANAGEMENT CO/CA/
Security
Biogen Inc. COM
Symbol
BIIB
Shares outstanding
146,614,676 shares
Disclosed Ownership
14,954,697 shares
Ownership
10%
Form type
SCHEDULE 13G/A
Filing time
13 Nov 2025, 20:28:22 UTC
Date of event
30 Sep 2025

Reporting Managers (1)

Name Ownership Shares Owned sole voting power shared voting power Signature Title CIK
PRIMECAP MANAGEMENT CO/CA/ 10% 14,954,697 14,859,187 0 Jorge A. Rodriguez Deputy Chief Compliance Officer