DEFA14A 1 d916837ddefa14a.htm DEFA14A

Your Vote Counts! BIOGEN INC. 2025 Annual Meeting Vote by June 16, 2025 11:59 PM ET BIOGEN INC. 225 BINNEY STREET CAMBRIDGE, MA 02142 V69530-P28515 You invested in BIOGEN INC. and it’s time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy materials for the stockholder meeting to be held on June 17, 2025. Get informed before you vote View the 2025 Notice and Proxy Statement and 2024 Annual Report with Form 10-K online OR you can receive a free paper or email copy of the material(s) by requesting prior to June 3, 2025. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. For complete information and to vote, visit www.ProxyVote.com Control # Smartphone users Vote Virtually at the Meeting* Point your camera here and June 17, 2025 vote without entering a 9:00 a.m. Eastern Time control number Virtually at: www.virtualshareholdermeeting.com/BIIB2025 *Please check the meeting materials for any special requirements for meeting attendance.

Vote at www.ProxyVote.com THIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters. Board Voting Items Recommends 1. Election of Directors. To elect the 11 nominees identified in the accompanying Proxy Statement to our Board of Directors to serve for a one-year term extending until our 2026 annual meeting of stockholders and their successors are duly elected and qualified. Nominees: 1a. Caroline D. Dorsa For 1b. Maria C. Freire For 1c. William A. Hawkins For 1d. Susan K. Langer For 1e. Jesus B. Mantas For 1f. Lloyd Minor For 1g. Menelas Pangalos For 1h. Monish Patolawala For 1i. Eric K. Rowinsky For 1j. Stephen A. Sherwin For 1k. Christopher A. Viehbacher For 2. To ratify the selection of PricewaterhouseCoopers LLP as our independent registered public accounting firm for fiscal For year ending December 31, 2025. 3. Say on Pay—To hold an advisory vote on executive compensation. For 4. To transact such other business as may be properly brought before the annual meeting and any adjournments or postponements. Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Delivery Settings”. V69531-P28515