DEF 14A of Biogen Inc., Apr 28, 2026

DEF 14A of Biogen Inc.

Filed Apr 28, 2026 · FY20250001193125-26-187303

Open on EDGAR

  1. Proxy Statement Summary

    Proxy Statement Summary This summary highlights important information you will find in this Proxy Statement. As it is only a summary, please review the complete Proxy Statement before you vote.

  2. Proxy Statement Summary

    | Annual Meeting Information |

  3. Proxy Statement Summary

    | DATE: | Tuesday, June 9, 2026 | | TIME: | 9:00 a.m. Eastern Time | | LOCATION: | Online only at www.virtualshareholdermeeting.com/BIIB2026 You will not be able to attend the 2026 Annual Meeting in person. | | RECORD DATE: | April 21, 2026 |

  4. Proxy Statement Summary

    | Voting Matters and Vote Recommendation |

  5. Proxy Statement Summary

    | Matter Management Proposals: | Our Board Recommendation | Page Number for more detail | | Proposal 1—Election of Directors | FOR each nominee | 2 | | Proposal 2—Ratificationof the Selection of PricewaterhouseCoopers LLP (PwC) as our Independent Registered Public Accounting Firm for the fiscal year ending December 31, 2026 | FOR | 25 | | Proposal 3—Advisory Vote on Executive Compensation | FOR | 28 |

  6. Proxy Statement Summary

    | How to Vote |

  7. Proxy Statement Summary

    | Vote Right Away Through Advance Voting Methods | | Vote During Meeting | | | | Vote by Internet Using Your Computer Go to www.proxyvote.com and enter the Control Number provided in your Notice of Internet Availability of Proxy Materials (Notice), or if you received a printed copy of proxy materials, on your proxy card or voting instruction form. | | Vote During the Meeting See Part 1 –“General Information About the Meeting” for details on how to vote during the Annual Meeting. | | | Vote by Telephone Call 800-690-6903 or the telephone number on your Notice, proxy card or voting instruction form. You will need the Control Number provided on your Notice, or if you received a printed copy of the proxy materials, on your proxy card or voting instruction form. | | | | | Vote by Mail Complete, sign and date the proxy card or voting instruction form and mail it in the accompanying pre-addressed envelope. | | |

  8. Proxy Statement Summary

    | 2026 Proxy Statement | -1- |

  9. Proxy Statement Summary

    We are asking our stockholders to elect the 10 director nominees listed below to each serve a one-year term extending until our 2027 annual meeting of stockholders and until he or she is duly elected and qualified, unless they resign or are removed:

  10. Proxy Statement Summary

    | Maria C. Freire | Lloyd Minor | Eric K. Rowinsky | | William A. Hawkins | Menelas Pangalos | Stephen A. Sherwin | | Susan K. Langer | Monish Patolawala | Christopher A. Viehbacher | | Jesus B. Mantas | | |

  11. Proxy Statement Summary

    Our Board has nominated these 10 individuals based on its carefully considered judgment that the skills, contributions, backgrounds, perspectives and experiences of our nominees qualify them to serve on our Board. As described in detail below, our nominees have considerable professional and business expertise. We know of no reason why any nominee would be unable to accept nomination or election. All nominees have consented to being named in this Proxy Statement and to serve if elected. To be elected, a director nominee must receive the affirmative vote of a majority of the votes cast. Abstentions and broker non-votes, if any, are not considered votes cast under our bylaws and will have no effect on the results of this vote. For additional information please see also “What vote is required to approve each proposal and how are votes counted?” on page 68. If any nominee is unable to serve on our Board, the stock represented by your proxy will be voted for the election of such other person as may be nominated by our Board or alternatively, the number of directors may be reduced accordingly by our Board. In addition, in compliance with all applicable state and federal laws and regulations, we will file an amended proxy statement and proxy card that, as applicable, (1) identifies the alternate nominee(s) and (2) discloses that such nominee(s) has consented to being named in the revised proxy statement and to serve if elected.

  12. Proxy Statement Summary

    | Nominees to the Board | Independent | Age* | Director Since | Audit Committee | Corporate Governance Committee | Compensation and Management Development Committee | Other Public Company Boards | | Maria C. Freire** | ✓ | 71 | 2021 | | M | M | 2 | | William A. Hawkins | ✓ | 72 | 2019 | M | M | | 2 | | Susan K. Langer | ✓ | 35 | 2023 | | | M | — | | Jesus B. Mantas | ✓ | 57 | 2019 | | | C | 1 | | Lloyd Minor | ✓ | 68 | 2024 | M | | | 1 | | Menelas Pangalos | ✓ | 59 | 2025 | | | M | 1 | | Monish Patolawala | ✓ | 56 | 2024 | C | | | — | | Eric K. Rowinsky | ✓ | 69 | 2010 | | M | M | 2 | | Stephen A. Sherwin | ✓ | 77 | 2010 | M | | | 2 | | Christopher A. Viehbacher | | 66 | 2022 | | | | — |

  13. Proxy Statement Summary

    * Age and Committee memberships are as of April 21, 2026. ** Ms. Dorsa has notified the Board that she is not standing for reelection at the 2026 Annual Meeting. Effective immediately after the 2026 Annual Meeting, Dr. Freire will become Chair of the Board. The Board will appoint a new CGC Chair following the 2026 Annual Meeting. C – Chair; M – Member

  14. Proxy Statement Summary

    | 2026 Proxy Statement | -2- |

  15. Proxy Statement Summary

    Summary of Director Nominee Core Experiences and Skills Our Board is comprised of highly qualified leaders in their respective fields, and as a group possesses a deep and broad set of skills, contributions, backgrounds, perspectives and experiences that facilitate strong oversight and strategic direction for a pioneering biotechnology company. Our Board and our CGC believe the skills, contributions, backgrounds and experiences of our directors provide us not only with a wide range, but also the appropriate mix, of perspectives to effectively address our evolving needs and represent the best interests of our stockholders. The following chart summarizes the competencies and background of each director nominee. The details of each nominee’s competencies are included in each nominee’s biography.

  16. Proxy Statement Summary

    | Key Skills and Experience | | | | | | | | | | | | Executive Leadership & Business Operations Experience serving in a senior leadership role develops skills in core management areas and provides a valuable practical understanding of the operations of complex organizations | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | | Commercial Knowledge of creating and sustaining revenue streams facilitates oversight of efficient and robust revenue generation | | ✓ | ✓ | ✓ | | ✓ | ✓ | | | ✓ | | Cybersecurity/Information Technology/AI Experience understanding and overseeing information technology and cybersecurity matters is critical to mitigating risks to our business and to Board oversight of Biogen’s actions to address innovation and competitiveness in a rapidly evolving technological age | | | | ✓ | ✓ | | ✓ | | | | | Drug Development Expertise of drug development increases successful navigation of the highly regulated life sciences market | ✓ | | ✓ | | ✓ | ✓ | | ✓ | ✓ | ✓ | | Healthcare & Pharma Leadership Experience as an executive and/or in an operational role at a pharmaceutical or biotechnology focused organization or company provides directors with a deep understanding of Biogen’s business and key strategic and operational considerations | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | | Finance and Accounting Expertise in finance, capital markets, mergers and acquisitions, investment management and financial reporting processes enables directors to effectively monitor and assess Biogen’s operating and strategic performance and capital allocation decisions, and oversee accurate financial reporting and robust controls | ✓ | ✓ | | ✓ | ✓ | | ✓ | | ✓ | ✓ | | International Business Global market expertise enhances oversight of strategy development and execution, supply chain and compliance across markets | ✓ | ✓ | | ✓ | | ✓ | ✓ | | | ✓ | | Public Board Service Corporate governance fluency ensures stockholder interests serve as input to discussions and informs Board decisions | ✓ | ✓ | | ✓ | ✓ | ✓ | | ✓ | ✓ | ✓ | | Government and Public Policy Understanding of the complex regulatory and governmental environment in which Biogen operates allows the Board to oversee the company’s long-term strategy by incorporating current and potential changes in public policy and regulation | ✓ | ✓ | | ✓ | ✓ | ✓ | ✓ | | ✓ | ✓ |

  17. Proxy Statement Summary

    | 2026 Proxy Statement | -3- |

  18. Proxy Statement Summary

    | Key Skills and Experience | | | | | | | | | | | | Medicine and Scientific Research Knowledge of relevant sciences and research experience provides Directors with a deep understanding of Biogen’s key therapeutic areas and an appreciation for our mission to deliver breakthroughs that change patients’ lives | ✓ | | | ✓ | ✓ | ✓ | | ✓ | ✓ | | | Background | | | | | | | | | | | | Gender | F | M | F | M | M | M | M | M | M | M | | Racially/Ethnically Diverse | ✓ | | | ✓ | | | ✓ | | | | | Did not Disclose Demographic Background | | | ✓ | | | | | | | |

  19. Proxy Statement Summary

    | 2026 Proxy Statement | -4- |

  20. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE VOTED “FOR” THE ELECTION OF THE NOMINEES UNLESS OTHERWISE SPECIFIED. Set forth below is biographical information for each nominee and a summary of the specific skills, contributions, background and experiences which led our Board to conclude that each nominee should serve on the Board at this time.

  21. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | Maria C. Freire, Ph.D., Independent Chair (after 2026 Annual Meeting), fmr. President and Executive Director, Foundation for the National Institutes of Health | | | Director since 2021 Age 71 Board Committees Compensation and Management Development Corporate Governance Key Skills • Executive Leadership and Business Operations • Drug Development • Healthcare and Pharma Leadership • Finance and Accounting • International Business • Public Board Service • Government and Public Policy • Medicine and Scientific Research | Relevant Expertise Dr. Freire has significant knowledge and experience with respect to medical research, the pharmaceutical industry and government healthcare policymaking. Dr. Freire’s strong public policy and government experience vitally enhances the Board’s perspective of significant issues affecting the highly regulated life sciences industry. Career Highlights • President and Executive Director, Foundation for the National Institutes of Health (NIH) (2012 – 2021) • President and Director, Albert and Mary Lasker Foundation (2008 – 2012) • President and CEO, Global Alliance for TB Drug Development (2001 – 2008) • Director of the Office of Technology Transfer, NIH (1995 – 2001) Other Public Company Boards Current • Alexandria Real Estate Equities, Inc. (since 2012) • Exelixis, Inc. (since 2018) Other Boards & Awards • Science Board of the U.S. Food and Drug Administration (FDA) • World Health Organization Commission on Intellectual Property Rights, Innovation and Public Health, United Nations Secretary General’s High-Level Panel on Access to Medicines • Member, National Academy of Medicine and the Council on Foreign Relations • 2017 Gold Stevie Award for “Woman of the Year,” the U.S. Department of Health and Human Services Secretary’s Award for Distinguished Service, the Arthur S. Fleming Award and the Bayh-Dole Award Education • B.S. from the Universidad Peruana Cayetano Heredia (Lima, Peru) • Ph.D. in Biophysics from the University of Virginia |

  22. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | 2026 Proxy Statement | -5- |

  23. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | William A. Hawkins, fmr. Chairman and Chief Executive Officer, Medtronic, Inc. | | | Director since 2019 Age 72 Board Committees Audit Corporate Governance Key Skills • Executive Leadership and Business Operations • Commercial • Healthcare and Pharma Leadership • Finance and Accounting • International Business • Public Board Service • Government Public Policy | Relevant Expertise Mr. Hawkins has significant executive and board leadership experience in the healthcare industry both domestic and international. Mr. Hawkins’ unique perspective enhances the Board’s oversight of development and implementation of Biogen’s global strategic plans. Career Highlights • Senior Advisor to EW Healthcare Partners, a life sciences private equity firm (since 2017) • President and CEO, Immucor, a global leader in transfusion and transplant medicine (2011 – 2015) • Chairman and CEO, Medtronic, Inc. (2002 – 2011) • President and CEO, Novoste Corporation, an interventional cardiology company (1998 – 2001) Other Public Company Boards Current • Chair, Bioventus, Inc. (since 2016) • MiMedx Group, Inc. (since 2020) Prior • Avanos Medical, Inc. (2015 – 2021) Other Boards & Awards • Director, Virtue Labs, Enterra, Lacuna Medical, Cirtec Medical Corp. and Baebies, Inc., all private life sciences companies • Member, National Academy of Engineering, and AIMBE College of Fellows Education • B.Sc. in Electrical and Biomedical Engineering (dual) from Duke University • M.B.A. from the University of Virginia’s Darden School of Business |

  24. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | Susan Langer, Founding President & Chief Business Officer at Souffle Therapeutics | | | Director since 2023 Age 35 Board Committee Compensation and Management Development Key Skills • Executive Leadership and Business Operations • Commercial • Drug Development • Healthcare and Pharma Leadership | Relevant Expertise Ms. Langer has significant experience and knowledge of the biopharmaceutical industry and deep connections within the biotechnology, start-up and venture capital ecosystems. That expertise, coupled with her knowledge of Biogen’s operations, enhances the Board’s ability to nimbly evaluate growth opportunities as well as long-term investments. Career Highlights • Founding President and Chief Business Officer, Souffle Therapeutics (since 2021) • Founding President, Kojin Therapeutics (2020 – 2021) • Chief Business Officer, Paratus Sciences (2021 – 2023) • Director, Guava Partners (since 2021) • Venture Partner, Old Silver VC LLC (2020 – 2023) • Head of Corporate Strategy and other roles at Biogen (2013 – 2019) Other Public Company Boards • None Education • B.A. in Science & Technology Studies from Cornell University |

  25. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | 2026 Proxy Statement | -6- |

  26. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | Jesus B. Mantas, fmr. Global Managing Partner, IBM Business Transformation Services | | | Director since 2019 Age 57 Board Committee Compensation and Management Development (Chair) Key Skills • Executive Leadership and Business Operations • Commercial • Information Technology/Cybersecurity/AI • Public Board Service • International Business • Government and Public Policy | Relevant Expertise Mr. Mantas has over 30 years of experience in global business operations, information technology, data science and artificial intelligence gained through global strategy and operating management roles across Europe, North America and Latin America. His expertise enhances Board perspectives on global operating scale, business strategy, culture change, managing risks, applying technology to improve business performance, seeking inclusion and developing talent and succession plans in multi-cultural environments. Career Highlights • Global Managing Partner, IBM Global Business Services (2022 – 2025) • Senior roles at IBM (2002 – 2022) including: ○ Global Managing Partner, Strategy, Innovation and Corporate Development ○ Global Managing Partner, IBM Business Consulting ○ General Manager, IBM Business Process Outsourcing ○ Managing Partner and General Manager, IBM Global Business Services Latin America ○ Senior Partner, IBM Global Business Services • Partner, High Technology Practice, PricewaterhouseCoopers Consulting (1997 – 2002) • Adjunct Professor, University of California Irvine, Graduate School of Management, Paul Merage School of Business (1997 – 2001) • Second Lieutenant, Air Force of Spain (1993) Other Public Company Boards • International Flavors and Fragrances Inc. (since 2025) Education • B.S. in Telecommunications – Software Engineering, Universidad Politécnica de Madrid (Madrid, Spain) • Degree in Business Administration, Universidad Politécnica de Madrid (Madrid, Spain) • Corporate Governance – Harvard Business School |

  27. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | Lloyd Minor, M.D., Dean of the Stanford University School of Medicine | | | Director since 2024 Age 68 Board Committee Audit Key Skills • Executive Leadership and Business Operations • Drug Development • Cybersecurity • Healthcare and Pharma Leadership • Finance and Accounting • Government and Public Policy • Medicine and Scientific Research | Relevant Expertise Dr. Minor serves as the Dean of the Stanford University School of Medicine and Vice President Medical Affairs at Stanford University, where he is instrumental in establishing strategy across the Stanford Medicine enterprise, leading health and medicine matters at Stanford in research, clinical care and education. This expertise enhances Board oversight of strategic goals and R&D. Career Highlights • Carl and Elizabeth Naumann Dean of the Stanford University School of Medicine (since 2012) • Vice President for Medical Affairs, Stanford University (since 2023) • Provost and Senior Vice President for Academic Affairs, Johns Hopkins University (2009 – 2012) • Director of the Department of Otolaryngology – Head & Neck Surgery, Johns Hopkins University (2003 – 2009) Other Public Company Boards • Caris Life Sciences, Inc. (since 2021) Education • Sc.B. from Brown University • M.D. from Brown University |

  28. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | 2026 Proxy Statement | -7- |

  29. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | Sir Menelas (Mene) Pangalos, Ph.D., fmr. Executive Vice President of Biopharmaceuticals R&D at AstraZeneca | | | Director since 2025 Age 59 Board Committee Compensation and Management Development Key Skills • Executive Leadership and Business Operations • Commercial • Drug Development • Healthcare and Pharma Leadership • International Business • Public Board Service • Government and Public Policy • Medicine and Scientific Research | Relevant Expertise Dr. Pangalos has over 30 years of experience researching and developing medicines gained through research and development roles across a number of pharmaceutical and biotechnology companies. Dr. Pangalos’ expertise enhances Board perspectives on the development and execution of corporate strategy, drug development and managing risks. Career Highlights • Executive Vice President of Biopharmaceuticals R&D, AstraZeneca (2019 – 2024) • Executive Vice President of Early R&D, AstraZeneca (2010 – 2018) • Senior Vice President, Pfizer (2008 – 2010) • Vice President Neuroscience, Wyeth (2003 – 2008) • Fellow of the Royal Society, the Academy of Medical Sciences, the Royal Society of Biology and Clare Hall, University of Cambridge Other Public Company Boards • Absci Corporation (since 2024) Education • Bachelor of Science in Biochemistry and Molecular Biology from Imperial College London • Ph.D. in Neuropharmacology from University College London |

  30. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | Monish Patolawala, Chief Financial Officer at ADM | | | Director since 2024 Age 56 Board Committee Audit (Chair) Key Skills • Executive Leadership and Business Operations • Commercial • Information Technology/Cybersecurity/AI • Finance and Accounting • International Business • Government and Public Policy | Relevant Expertise Mr. Patolawala has more than 25 years of experience leading financial operations and business for global industrial and healthcare companies. At Archer-Daniels Midland, he oversees the company’s global finance and accounting, global business services, global technology and enterprise strategy functions. Mr. Patolawala’s experience enhances the Board’s perspectives on financial and business operations, technology and strategy. Career Highlights • CFO, Archer-Daniels Midland (since 2024) • President and CFO, 3M Company (2020 – 2024) • CFO of GE Healthcare (2015 – 2020) • Variety of roles of increasing responsibility at General Electric Company (1994 – 2020) Other Public Company Boards • None Certifications • Chartered Accountant from the Institute of Chartered Accountants of India • Cost and Works Accountant from the Institute of Cost and Works Accountants of India Education • B. Com from St. Joseph’s College of Commerce (Bangalore, India) |

  31. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | 2026 Proxy Statement | -8- |

  32. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | Eric K. Rowinsky, M.D., President of Inspirna | | | Director since 2010 Age 69 Board Committees Compensation and Management Development Corporate Governance Key Skills • Executive Leadership and Business Operations • Drug Development • Healthcare and Pharma Leadership • Public Board Service • Medicine and Scientific Research | Relevant Expertise Dr. Rowinsky has extensive research and drug development and regulatory experience and broad scientific and medical knowledge. His experience leading teams that have registered more than twelve novel therapies for patients with advanced cancers enhances the Board’s oversight of Biogen’s R&D and quest to pioneer breakthrough innovations within the highly regulated life sciences industry. Career Highlights • President, Inspirna, a privately held life science company (since 2015), and Executive Chairman (2016 – 2021) • Chief Medical Officer, Hummingbird Biotherapeutics (2020 – 2023) • Chief Scientific Officer, Clearpath Development, Inc. (2016 – 2021) • Head of R&D, Chief Medical Officer, Stemline Therapeutics (2012 – 2015) • CEO, Primrose Therapeutics, Inc., a biotech start-up (2010 – 2011) • Chief Medical Officer, and Executive Vice President, ImClone Systems (2005 – 2010) Other Public Company Boards Current • Purple Biotech Ltd. (since 2019) • Verastem, Inc. (since 2017) Prior • Fortress Biotech Inc. (2010 – 2024) Other Boards & Awards • Director of the Institute, and Director of Clinical Research, Cancer Therapy & Research Center’s Institute for Drug Development (1996 – 2004) • Associate Professor of Oncology at the Johns Hopkins School of Medicine (1988 – 1996) • Director, Scientific Counselors of the National Cancer Institute Level Panel on Access to Medicines Education • B.A. in Liberal Arts, from New York University • M.D. from Vanderbilt University School of Medicine |

  33. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | Stephen A. Sherwin, M.D., Clinical Professor of Medicine at UCSF | | | Director since 2010 Age 77 Board Committee Audit Key Skills • Executive Leadership and Business Operations • Drug Development • Healthcare and Pharma Leadership • Finance and Accounting • Public Board Service • Government and Public Policy • Medicine and Scientific Research | Relevant Expertise Dr. Sherwin has extensive knowledge of the life sciences industry through his advisory work in life sciences, and patient care and teaching in his specialty of medical oncology, as well as founding and leading life sciences companies. Dr. Sherwin’s more than 30 years of industry experience significantly enhances Board oversight and development of Biogen’s strategy and execution. Career Highlights • Clinical Professor of Medicine at the University of California, San Francisco (since 2010) • Volunteer Attending Physician in Hematology-Oncology at the Zuckerberg San Francisco General Hospital (since 2010) • Advisory partner, Third Rock Ventures, LLC (since 2016) • Chairman and Co-founder, Ceregene, a life sciences company acquired by Sangamo Biosciences (2001 – 2013) • Chairman and Co-founder, Abgenix, Inc, an antibody company acquired by Amgen (1996 – 2006) • CEO and Chairman, Cell Genesys, Inc., a life sciences company merged with BioSante Pharmaceuticals, Inc. (now ANI Pharmaceuticals, Inc.) (1994 – 2009) Other Public Company Boards Current • Neurocrine Biosciences Inc. (since 1999) • Innovent Biologics, Inc. (since 2025) Prior • Epiphany Technology Acquisition Corp. (2022 – 2023) • Bios Special Acquisition Corporation (2021 – 2023) • Aduro Biotech, Inc (2015 – 2020) Education • B.A. in Biology from Yale University • M.D. from Harvard Medical School |

  34. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | 2026 Proxy Statement | -9- |

  35. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | Christopher A. Viehbacher, President and Chief Executive Officer, Biogen Inc. | | | Director since 2022 Age 66 Key Skills • Executive Leadership and Business Operations • Commercial • Drug Development • Healthcare and Pharma Leadership • Finance and Accounting • International Business • Public Board Service • Government and Public Policy | Relevant Expertise Mr. Viehbacher has extensive international experience in both large pharmaceutical companies and entrepreneurial biotech companies. Mr. Viehbacher brings a keen understanding of the complexities involved in running a multibillion-dollar global pharmaceutical business as well as an appreciation for the value of innovation. Career Highlights • President and CEO, Biogen Inc. (since 2022) • Managing Partner, Gurnet Point Capital, a Boston based investment fund (2015 – 2022) • Global CEO of Sanofi S.A. (2008 – 2014) • Various roles, GlaxoSmithKline (1984 – 2008) Other Public Company Boards Prior • Pure Tech plc (2015 – 2023) Other Boards & Awards • Trustee, Northeastern University • Board of Fellows, Stanford Medical School • Braveheart Bio, Inc. Education • B. Comm. from Queen’s University (Kingston, Canada) |

  36. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | THE BOARD OF DIRECTORS RECOMMENDS A VOTE FOR EACH OF THE NAMED NOMINEES. |

  37. OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE NAMED NOMINEES. PROXIES WILL BE

    | 2026 Proxy Statement | -10- |

  38. Committees and Meetings

    Committees and Meetings Our Board met six times in 2025. Our Board also has three standing committees, the Audit Committee, CMDC and CGC. The principal functions of each committee, the committee composition as of December 31, 2025, and the number of committee meetings held in 2025 are described in the table below. The Chair of each committee periodically reports to our Board on committee deliberations and decisions. Our Board maintains charters of each of its committees and the charters are reviewed at least annually. The charters for each of the committees are posted on our website, www.biogen.com, under the “Corporate Governance” subsection of the “Investors” section of the website. Our Corporate Governance Principles, together with our committee charters, Bylaws, Certificate of Incorporation and Code of Business Conduct, comprise our governance framework.

  39. Committees and Meetings

    | Committee | Function | 2025 Members | Meetings in 2025 | | Audit | Assists our Board in its oversight of: • the integrity of our financial statements; • our accounting and financial reporting processes; • the independence, qualifications and performance of our independent registered public accounting firm; • the effectiveness of the company’s internal control over financial reporting; • our global tax strategy, compliance and tax audit processes; • our internal audit and corporate compliance functions; • our financial strategy, policies and practices; and • the adequacy and effectiveness of the company’s insurance programs. Our Audit Committee has the sole authority and direct responsibility for the appointment, compensation, retention, evaluation and oversight of the work of our independent registered public accounting firm. | Monish Patolawala† (Chair) Lloyd Minor William A. Hawkins† Stephen A. Sherwin† | 7 | | Compensation and Management Development | Assists our Board with oversight of executive compensation and management development, including: • recommending to our Board for approval the compensation of our CEO and approving the compensation of our other NEOs; • administration of our short- and long-term incentive plans; • reviewing executive and senior management development programs and succession plans; and • recommending to our Board the compensation of our non-employee directors. | Jesus B. Mantas (Chair) Maria C. Freire Susan K. Langer Menelas Pangalos Eric K. Rowinsky | 7 | | Corporate Governance | Assists our Board oversight of corporate governance, including: • identifying, selecting, evaluating and recommending Board nominees to stand for election at the annual meeting of stockholders and fill vacancies as they arise; • overseeing the Corporate Governance Principles and Code of Business Conduct and its application to Board members; • overseeing our Board and committee evaluation process; and • oversight of our lobbying priorities and activities, including associations with certain trade and/or legislative organizations. | Caroline D. Dorsa (Chair)†* Maria C. Freire William A. Hawkins Eric K. Rowinsky | 4 |

  40. Committees and Meetings

    | † Determined by our Board to be an Audit Committee financial expert. |

  41. Committees and Meetings

    | * Ms. Dorsa has notified the Board that she is not standing for reelection at the 2026 Annual Meeting. The Board will appoint a new CGC Chair following the 2026 Annual Meeting. |

  42. Committees and Meetings

    | • | Attendance at Board and Committee Meetings. No director nominee attended fewer than 75% of the total number of meetings of our Board and the committees on which he or she served during 2025. |

  43. Committees and Meetings

    | • | Executive Sessions. Under our Corporate Governance Principles, the independent directors of our Board are required to meet without management present, which we refer to as an executive session, at least four times each year and may also meet without management present at such other times as determined by our Chair or if requested by at least two other directors. In 2025, the independent directors of our Board met without management present four times. Each committee of our Board also had numerous executive sessions throughout the year. |

  44. Committees and Meetings

    | • | Attendance at Stockholder Meeting. We expect all of our directors and director nominees to attend our annual meetings of stockholders. All directors who were nominees for election as directors at the 2025 Annual Meeting attended the 2025 Annual Meeting. |

  45. Committees and Meetings

    | 2026 Proxy Statement | -16- |

  46. Director Compensation

    Director Compensation This section describes our compensation program for our non-employee directors and shows the compensation granted or paid to or earned by our non-employee directors during 2025. Mr. Viehbacher, our President and CEO, did not receive any additional compensation for his service on our Board. Our CMDC has the authority to evaluate and make recommendations to our Board regarding non-employee director compensation which includes an annual cash retainer, additional cash retainer for committee service and equity award grant. The cash retainers and equity awards are approved by our Board, with the Chair abstaining from voting on the Chair’s equity award. Our CMDC periodically reviews our non-employee director compensation practices against the practices of an appropriate peer group and our CMDC has the authority to retain consultants to advise on non-employee director compensation matters, including in support of our CMDC’s periodic review of non-employee director compensation practices. No executive officer has any role in determining or recommending the form or amount of non-employee director compensation.

  47. 2025 Director Compensation

    2025 Director Compensation

  48. 2025 Director Compensation

    | Name | Fees Earned or Paid in Cash | Stock Awards(1) | All Other Compensation(2) | Total | | Caroline D. Dorsa | $230,000 | $399,930 | — | $629,930 | | Maria C. Freire | $155,000 | $299,947 | $2,500 | $457,447 | | William A. Hawkins | $162,500 | $299,947 | — | $462,447 | | Susan K. Langer | $140,000 | $299,947 | — | $439,947 | | Jesus B. Mantas | $155,000 | $299,947 | $5,000 | $459,947 | | Lloyd Minor | $140,000 | $299,947 | — | $439,947 | | Menelas Pangalos | $140,000 | $299,947 | — | $439,947 | | Monish Patolawala | $147,500 | $299,947 | — | $447,447 | | Eric K. Rowinsky | $155,000 | $299,947 | — | $454,947 | | Stephen A. Sherwin | $140,000 | $299,947 | — | $439,947 |

  49. 2025 Director Compensation

    Notes to the 2025 Director Compensation Table

  50. 2025 Director Compensation

    | (1) Represents the grant date fair value of RSU awards made in 2025 to non-employee directors under the 2024 Omnibus Equity Plan, as described in the narrative preceding this table. These RSUs are scheduled to vest in full and be settled in stock at the earlier of (i) the first anniversary of the grant date or (ii) the 2026 Annual Meeting, generally subject to continued service. Grant date fair values were computed in accordance with ASC 718, excluding the effect of estimated forfeitures, and determined by multiplying the number of RSUs awarded by the fair market value of the company’s common stock on the relevant grant date. |

  51. 2025 Director Compensation

    | (2) Represents matching contributions made in 2025 by the Biogen Foundation on behalf of the director pursuant to the terms of a matching gift program offered by the Biogen Foundation to all U.S. employees and non-employee directors of Biogen. Under the matching gift program, the Biogen Foundation matches gifts to eligible U.S.-based non-profit organizations, in accordance with the Biogen Foundation’s guidelines, up to an annual maximum per donor amount of $5,000 per calendar year and up to an aggregate program total of $1.5 million per calendar year. |

  52. Proposal 3 – Advisory Vote on Executive Compensation

    Proposal 3 – Advisory Vote on Executive Compensation Our CD&A, which appears below, provides an overview of our 2025 executive compensation program, as well as a description of the compensation decisions that our CMDC and Board made with respect to the 2025 compensation of our NEOs. This year our CD&A also includes a discussion of the stockholder engagement we had in 2025 specifically related to executive compensation. Our Board is asking that stockholders cast a non-binding, advisory vote FOR the following resolution: “RESOLVED, that the compensation paid to the company’s named executive officers, as disclosed pursuant to Item 402 of Regulation S-K, including the CD&A, compensation tables and narrative discussion, is hereby APPROVED.” Because the Advisory Vote on Executive Compensation asks for a non-binding, advisory vote, there is no “required vote” that would constitute approval. Abstentions will have the effect of a vote against the proposal, and broker non-votes, if any, will not have any effect on the results of those deliberations. Although the vote you are being asked to cast is non-binding, we value the views of our stockholders, and our CMDC and our Board will consider the outcome of the vote when making future compensation decisions for our NEOs. As we describe in our CD&A, our executive compensation programs embody a strong pay-for-performance philosophy that supports our business strategy and aligns the interests of our executives with those of our stockholders. In particular, our executive compensation programs reward financial, strategic and operational performance, and the goals set under our incentive plans support the company’s short- and long-range plans. In addition, to discourage excessive risk taking, we maintain policies for stock ownership, and our equity and short-term incentive programs have provisions providing for the recoupment of compensation. We also cap payments under our short-term incentive program, and we generally require multi-year vesting periods for LTI awards.

  53. OUR BOARD OF DIRECTORS RECOMMENDS THAT STOCKHOLDERS VOTE

    Dear Fellow Stockholders, Biogen continues to progress its portfolio across neuroscience, immunology and rare diseases. Within that context, the Biogen Compensation and Management Development Committee ensures the alignment of executive compensation, balancing near-term execution and long-term stockholder value creation. In 2025, the CMDC set reasonable, challenging performance goals after careful evaluation of risks and opportunities. Management execution exceeded those goals, and the STI cash payout reflects this in-year performance. At the same time, the three-year rTSR underperformed peers as we transition our portfolio and, in alignment with our pay-for-performance design, executives (which we define as all employees at the level of Vice President and above) received no payout under the LTI performance program for the second year in a row. These outcomes appropriately reflect the progress we are making in the near-term and provide accountability for long-term stockholder value creation. We remain committed to continued engagement with our stockholders, and we have adjusted several aspects of our executive compensation plan in 2026 based on your feedback. Stockholder alignment: Engagement and 2026 enhancements informed by feedback Throughout 2025, including following the 2025 Annual Meeting, the CMDC and other independent directors continued to engage with our stockholders. We reached out to stockholders representing 62% of our outstanding shares of common stock, and 9 engaged with us, including 3 who voted against Say-On-Pay. This feedback plays a vital role in the ongoing evaluation and evolution of our executive compensation programs and directly shaped the 2026 program enhancements implemented. These changes are intended to further align executive compensation outcomes with delivering strong near-term operational performance and long-term stockholder returns, strengthen performance goal rigor, and enhance pay program transparency. Goal setting: Thorough and disciplined process The CMDC designed 2025 performance targets to be rigorous in the context of expected double digit decline in multiple sclerosis portfolio revenue driven by loss of exclusivity, partially offset by revenue growth from SKYCLARYS, LEQEMBI, SPINRAZA and ZURZUVAE. These goals reflected a balanced view of risks and opportunities, specific context of each of the products, and challenging goals for new product launches. To better align the compensation program with the portfolio changes, we added a new metric to capture the contribution of these products – growth product revenue – weighted 25% of the total STI score. We also added challenging pipeline progression targets consistent with accelerating the portfolio transition. At the end of 2025, strong commercial, research and development execution led to outperforming these targets for the year. In line with stockholder discussions encouraging increased performance-linked equity compensation to further motivate long-term stockholder value creation, we elected to calculate the 2025 CEO STI payout solely based on company results, without consideration of the CEO individual multiplier. In 2026, aligned with increased rigor on year-over-year performance, the CMDC implemented additional requirements that must be met before STI awards pay out above target: 2026 revenue metric will payout above target only if actual revenue is higher than prior year revenue, and 2026 EPS metric will payout above target only if EPS outperforms the 90th percentile analyst consensus (as of January 2026). In addition, we also implemented updates to LTI awards, specifically in the 2026 PSUs, in response to feedback we received from stockholders: we changed the requirement for PSUs to vest at target from 50th percentile to 55th percentile, to ensure above-median performance for target payout; and we added a pipeline metric (weighted 25%) to our 2026 PSUs to reflect the multi-year time horizon to develop, receive approval, and commercialize new treatments. Considering stockholder feedback, we also adjusted our peer group to more closely align with our revenue and market cap on average. With these changes, we believe the executive compensation program is aligned with stockholder feedback and remains competitive to attract and retain the talent needed to advance our strategy. Maintaining accountability for long-term stockholder returns LTI awards, which consist of both PSUs and RSUs, provide the greatest alignment of executive pay with stockholder experience, representing approximately 80% of CEO target compensation and 75% of the NEO pay mix (excluding the CEO). Annual LTI awards include 60% of total award value in PSUs to align value earned with sustainable long-term stockholder value creation. During our conversations, stockholders consistently agreed with our approach to evaluate our executive compensation plan based on realizable pay and not just based on awarded pay. The CEO’s new-hire PSUs (grant date value of $16.8 million) expired unearned in December 2025 delivering $0 because we did not achieve the threshold performance required. His new-hire stock options remain underwater with $0 earned value as of April 28, 2026. Further, the 2023–2025 PSU cycle and the 2022–2024 PSU cycle also expired with $0 value delivered because we did not achieve the threshold performance required. The CMDC did not provide any special awards or adjustments to offset these results, demonstrating our commitment to pay outcomes under Biogen’s pay-for-performance framework.

  54. The Compensation and Management Development Committee

    | Stockholder Feedback “What We Heard” | Actions Taken “What We Did” | Impact of Action “Why It Is Important” | | Limit payout opportunities and outcomes when Company financial performance is lower than the prior year. | ✓ Implemented additional requirements for our STI program starting in 2026 to limit payouts to target for each financial metric: • Revenue achievement component limited to target unless 2026 revenue surpasses 2025 revenue • Growth product revenue achievement component limited to target unless 2026 growth product revenue surpasses 2025 growth product revenue, and • EPS achievement component limited to target unless 2026 EPS exceeds the 90th percentile of analyst consensus (as of January 2026). | ✓ Limits financial metrics payouts when performance is lower than prior year. | | Include a pipeline performance metric into PSUs to incentivize long-term pipeline growth. | ✓ Added a new pipeline development metric to 2026 PSUs to incorporate our long-term sustainable growth goals. | ✓ Strengthens PSU alignment with a key driver of long-term stockholder value. | | Incentivize above-median performance. | ✓ Increased rTSR metric target performance requirement in our LTI Program from 50th to 55th percentile in 2026. | ✓ Increases the rigor required to achieve a 100% payout for the rTSR metric. | | Ensure appropriate benchmarking. | ✓ Updated 2026 peer group to remove three peers (Eli Lilly, AbbVie and Merck) and add BeOne Medicines. | ✓ Better aligns our peer group closer to Biogen’s size, revenue and market cap. | | Greater emphasis on linking CEO compensation to long-term value creation opportunities for Biogen. | ✓ In 2025, we calculated the CEO individual bonus multiplier component of the STI program solely based on Company results. | ✓ Shifts CEO short-term cash compensation to directly align with long-term company performance. | | Enhance disclosure of rationale and outcomes surrounding executive compensation programs and decisions, including rationale behind setting financial targets in the STI program. | ✓ Enhanced our disclosure to further explain our methodology for how and why we set financial targets in our executive compensation programs. ✓ Continued to disclose details of our achievements against metrics once performance periods have ended, including all financial metrics. | ✓ Supports alignment of interests between executive officers and stockholders. |

  55. Executive Summary of 2025 Achievements

    | Executive Compensation Philosophy | | | | | Our executive compensation philosophy is to reward executives for the creation of long-term stockholder value. We design performance-based executive compensation that rewards short-term achievements while maintaining accountability for long-term stockholder value creation. We also seek to maintain competitiveness with our peer group to enable us to attract and retain extraordinary leaders who perform at high levels and succeed in a demanding business environment. | | | | | Mission Focused and Business Driven | Competitively Advantageous | Performance Differentiated | Ownership Aligned | | We emphasize the importance of executing short-term goals while building and sustaining a foundation for long-term success in delivering meaningful and innovative therapies to patients leading to the creation of long-term stockholder value | We benchmark against companies we compete with for talent. Our compensation is designed to enable us to recruit, retain and motivate our leadership team to achieve exceptional results for the company and our stockholders | We align pay outcomes with company and individual performance and reward our best performers for exceeding expectations | We provide equity to all employees to align their interest with the company’s broader goal of creating long-term value for our stockholders |

  56. Our Named Executive Officers for 2025

    Our Named Executive Officers for 2025 Our named executive officers are listed below.

  57. Our Named Executive Officers for 2025

    | | Christopher A. Viehbacher President and Chief Executive Officer | | Susan H. Alexander Chief Legal Officer | | | Michael R. McDonnell Former Chief Financial Officer (retired March 2025) | | Priya A. Singhal Head of Development | | | Nicole C. Murphy Head of Pharmaceutical Operations and Technology | | Robin C. Kramer* Chief Financial Officer |

  58. Our Named Executive Officers for 2025

    | * Ms. Kramer was appointed Executive Vice President and Chief Financial Officer effective March 1, 2025. Mr. McDonnell ceased to be our Executive Vice President and Chief Financial Officer and retired on March 1, 2025. |

  59. Compensation Mix

    Compensation Mix The CMDC determines and allocates a mix of the compensation elements to ensure an appropriate level of performance-based compensation is apportioned between short-term and long-term compensation drivers aligned with our business goals, performance, and stockholder interests. We do not target a specific mix of value for each compensation element in either the program design or pay decisions. For our executive officers, including our NEOs, the most significant portion of their compensation is performance-based, with a particular emphasis on LTI awards (which consist of PSUs and RSUs), given the substantial impact these individuals have on Biogen’s future strategic direction.

  60. Realizable Pay Alignment

    Realizable Pay Alignment LTI value is directly tied to stock performance and comprises the largest portion of NEO compensation. This correlation ensures our NEOs’ realizable pay is aligned with and reflective of both company and individual performance. As an example, our 2023 PSUs did not achieve threshold performance. This resulted in a 0% payout for our NEOs at the end of the 2023-2025 performance period, decreasing their realizable pay and aligning executive pay outcomes to stockholder returns. The same PSU outcome was realized for the 2022-2024 PSU award cycle. It is important to note that the CMDC has not provided any special awards or adjustments to executives to offset these results further demonstrating our commitment to pay outcomes under our pay for performance programs.

  61. 2025 CEO Realizable Pay and Pay-for-Performance Alignment

    | • | The CEO’s new-hire PSUs, which had a grant date value of $16.8 million, vested at 0% in December 2025. This outcome was driven by both relative and absolute TSR performance that did not meet the threshold required to earn a payout. |

  62. 2025 CEO Realizable Pay and Pay-for-Performance Alignment

    | • | The CEO’s new-hire stock options, which have an exercise price of $301.85 per share, remain underwater and have $0 earned value at this time. These options have a remaining term of approximately 7 years. |

  63. CEO Aggregate Awarded Pay Versus Actual Pay: 2022 – 2025

    “Target Value” indicates target compensation awarded and includes: (1) salary paid each year, (2) target bonus opportunity in each year as disclosed in Biogen’s grant of plan-based awards table, and (3) target value of equity for 2022, 2024, and 2025 grants (assuming target performance) as disclosed in each year’s CD&A. “Realizable Value” indicates the current value of compensation awarded based on the following assumptions: (1) salary paid each year, (2) actual bonus earned each year as disclosed in the Summary Compensation Table, (3) 2022, 2024, and 2025 equity grants valued at Biogen’s 12/31/2025 closing price of $175.99 and (4) for PSUs, 2022 grants reflect that no payout was earned; 2024 and 2025 PSUs reflect projected payouts as of 12/31/2025, which is no payout on 2024 PSUs, 57% of target on 2025 PSUs tied to rTSR, and 100% of target on 2025 PSUs tied to EPS.

  64. Performance Goals and Target Setting Process

    Performance Goals and Target Setting Process In the first quarter of each year, our CMDC reviews and establishes the pay levels of each element of total compensation for our executive officers. Total compensation is comprised of base salary, a cash award under our STI program and LTI awards granted under our LTI program. The total compensation opportunity and mix of compensation elements for our executive officers are evaluated based on various factors such as individual, strategic and leadership achievements. Our CMDC considers these elements carefully when designing our executive compensation programs and believes that the use and weighting of multiple metrics, both quantitative and qualitative, can mitigate excessive risk taking and create appropriate incentives to focus on achievement of the company’s overall performance goals. For 2025, STI awards granted to our NEOs were made under our 2025 Performance-Based Management Incentive Plan, and awards under our LTI program were granted under the 2024 Omnibus Equity Plan. Awards made under our STI program are directly tied to the achievement of our company performance goals, which are designed to be aligned with the company’s short- and long-term strategic plans, as well as individual performance goals. Further information on our 2025 company performance goals can be found below under “2025 STI Program Design”. In 2025, our CMDC determined that PSU awards made under our LTI program for NEOs would incorporate two equally weighted measurements: an EPS growth metric and a relative stockholder return performance metric, comparing performance relative to a group of comparator companies, as described below under “2025 LTI Program”. We also made RSU grants under our LTI program that vest in approximately equal installments over three years beginning on the first anniversary of the grant date and are settled in shares of our common stock. RSUs, like PSUs, provide executives with ongoing incentive to increase stockholder value, as the ultimate value of the award is tied directly to our stock price. In setting our goals under our short- and long-term incentive programs, in addition to our internal forecasts, we consider analysts’ projections for our performance and the performance of companies in our peer group as well as broad economic and industry trends. We strive to establish challenging targets that result in payouts at or above target levels only when company performance warrants it. Our CMDC reviews and approves our metrics, goals, targets and levels of payout (e.g., threshold, target and maximum) for our executive incentive compensation plans and awards and for reviewing and determining actual performance results at the end of the applicable performance period.

  65. Performance Goals and Target Setting Process

    | 2026 Proxy Statement | -37- |

  66. Performance Goals and Target Setting Process

    In approving the performance goals for our executive officers and for the company under both the short- and long-term incentive programs, our CMDC also considers the alignment of such goals to our business, the degree of difficulty of attainment and the potential for the goals to encourage inappropriate risk-taking. Our CMDC has determined that the structures of our executive compensation programs do not put our patients, stockholders or the company at any material risk.

  67. Short Term Incentive Program

    Short Term Incentive Program

  68. 2025 Short Term Incentive Program

    2025 Short Term Incentive Program Our STI program is a cash incentive program that rewards near-term financial, strategic and operational company performance, as well as individual performance. Our CMDC reviews the annual target bonus opportunities for executive officers each year to ensure such opportunities remain competitive. The 2025 target bonus opportunities for NEOs, except Ms. Kramer, were unchanged from their respective 2024 bonus targets. Ms. Kramer was promoted in 2025 and her target bonus was prorated based on time served in her current and former role. The target annual bonus opportunity as a percentage of year-end annual base salary for each of our currently employed NEOs in 2025, compared to 2024, was as follows:

  69. 2025 Short Term Incentive Program

    | Name | 2025 Target | 2024 Target | | C. Viehbacher | 150% | 150% | | R. Kramer(1) | 80% | — | | S. Alexander | 80% | 80% | | P. Singhal | 75% | 75% | | N. Murphy | 75% | 75% |

  70. 2025 Short Term Incentive Program

    (1) Ms. Kramer’s awarded bonus was prorated for her time spent in her previous role and the CFO role.

  71. 2025 Short Term Incentive Program Design

    2025 Short Term Incentive Program Design Awards for our NEOs under our 2025 STI program were based on the achievement of company performance goals and individual performance goals. At the beginning of 2025 our CMDC set multiple company performance goals for our 2025 STI program and a payout multiplier, which we refer to as the Company Multiplier, ranging from 0% to 150%. The CMDC determined the Company Multiplier based on a pre-established scorecard for financial and strategic targets and its rigorous evaluation of the level of achievement and the weighting assigned to each goal and applied in the bonus calculation shown below. In addition, our 2025 STI program payouts were based on an assessment of each NEO’s individual performance, considering their achievement of pre-determined individual performance goals. Evaluating individual performance allows our CMDC (or our Board, in the case of our CEO) to increase or decrease each NEO’s bonus amount based on the NEO’s performance by applying an individual performance multiplier, ranging from 0% to 150%, which we refer to as the Individual Multiplier. We determined the individual annual bonus payments for 2025 using the following calculation:

  72. 2025 Short Term Incentive Program Design

    | Base Salaryx | Target Bonus (%)x | Company Multiplierx | Individual Multiplier |

  73. 2025 Short Term Incentive Program Design

    Consistent with our pay-for-performance philosophy, our 2025 STI program provided that if the Company Multiplier was less than 50%, there would be no payout, regardless of individual performance. Further, because the Individual Multiplier and the Company Multiplier each have a maximum of 150%, the combined multiplier result for each NEO is capped at 225% of target. In response to stockholder feedback requesting greater emphasis on linking payouts to long-term value creation opportunities, the CMDC elected to calculate the CEO individual bonus multiplier component of the STI program solely based on company results, and incentivize superior individual performance through LTI awards, shifting short-term cash compensation to directly align with long-term company performance.

  74. 2025 Goal Setting Process and Company Performance Results

    | Metric | Weight | Threshold | Target | Max | Achieved | Company Multiplier | | Financial Performance | | | | | | | | Revenue | 10% | $8,637M | $9,188M | $9,647M | $9,775M(1) | 150% | | Growth Revenue | 25% | $2,347M | $2,551M | $2,653M | $2,411M | 75% | | Non-GAAP Diluted Earnings Per Share** | 35% | $13.75 | $15.75 | $17.04 | $17.41(1) | 150% | | Pipeline Development | | | | | | | | Build and Advance Total Pipeline: ◾ Improve pipeline value creation while maximizing the potential to deliver meaningful medicines for patients | 25% | Achievement | | | Above Target(2) | 138% | | Corporate Responsibility | | | | | | | | Execute Corporate Responsibility strategy: ◾ Enroll representative patient population per clinical trial study targets, deliver health access for patients and advance a culture of excellence | 5% | Achievement | | | Above Target(3) | 120% | | Overall Annual Bonus Program Multiplier | | | | Company Multiplier | | 127%* |

  75. 2025 STI Program Awards

    2025 STI Program Awards Our CMDC, except with respect to Mr. Viehbacher whose final bonus determinations were made by our Board, determined that the final bonus awards under our 2025 STI program were as follows:

  76. 2025 STI Program Awards

    | Name | Year-end Salary (A) x | Target Bonus% (B) x | Company Multiplier (C) x | Individual Multiplier (D) = | Bonus Award (E) | | C. Viehbacher | $1,675,000 | 150% | 127% | 100%(1) | $3,190,875 | | R. Kramer(2) | $750,000 | 75% | 127% | 110% | $788,252 | | S. Alexander | $995,706 | 80% | 127% | 105% | $1,062,219 | | N. Murphy | $892,688 | 75% | 127% | 115% | $977,828 | | P. Singhal | $907,500 | 75% | 127% | 110% | $950,833 |

  77. 2025 STI Program Awards

    Notes to 2025 STI program Awards Table

  78. 2025 STI Program Awards

    | (1) The CMDC elected to calculate the CEO individual bonus multiplier component of the STI plan solely based on company results, and incentivize superior individual performance through LTI, shifting short-term cash compensation to directly align with long-term company performance |

  79. 2025 STI Program Awards

    | (2) Ms. Kramer’s target bonus percentage was prorated due to promotion in 2025 |

  80. 2025 Individual Performance Goals and Results

    2025 Individual Performance Goals and Results The Individual Multiplier reflects each NEO’s overall individual performance rating that is determined as part of our performance assessment process. Each NEO’s Individual Multiplier is based on an evaluation of his or her overall performance and consideration of the achievement of individual goals established at the beginning of the year. Goals may be both quantitative and qualitative. For 2025 Mr. Viehbacher recommended to our CMDC an Individual Multiplier for each actively employed NEO (other than himself) based on his assessment of their individual contributions for the year. In addition, the CMDC reviews on a qualitative basis each NEO’s other contributions to the company and business, leadership competencies and relative performance among all executive officers in determining Individual Multipliers. In its evaluation, the CMDC assigned Individual Multipliers to each actively employed NEO, other than Mr. Viehbacher, between 105% and 115% based on the accomplishments listed below. The CMDC recommended, and the Board approved, Mr. Viehbacher’s bonus with an Individual Multiplier of 100% and Company Multiplier of 127%. The CMDC elected to calculate the CEO individual bonus multiplier solely based on company results, and incentivize superior individual performance through LTI awards, shifting short-term cash compensation to directly align with long-term company performance. This decision emphasizes linking STI payout to the strategic and financial achievements of this year.

  81. Michael McDonnell

    Michael McDonnell

  82. Michael McDonnell

    | • | Mr. McDonnell was not eligible to receive a bonus under our 2025 STI program due to his retirement on March 1, 2025. |

  83. Looking Ahead: 2026 Company Performance Goal Setting

    | What We Changed | Why It Matters | | ✓ Payouts for 2026 revenue and growth revenue metrics cannot exceed target unless performance surpasses 2025 achievement. ✓ Payout for 2026 EPS metric cannot exceed target unless achievement outperforms 90th percentile of analyst consensus (as of January 2026). | ✓ Ensures payouts reflect true year over year improvement. |

  84. Long-Term Incentives

    Long-Term Incentives

  85. 2025 LTI Program

    2025 LTI Program Below is a summary of the mix of annual LTI awards granted to our NEOs in 2025.

  86. 2025 LTI Program

    | Terms | Performance Stock Units | Restricted Stock Units | | Proportion of Annual Target Grant | 60% | 40% | | Performance Period(s) | 3 years (2025-2027) | n/a | | Metrics & Weightings | Relative Total Stockholder Return: 50% Adjusted EPS CAGR: 50% | n/a | | Threshold / Maximum Payout (% of Target Award) | 0% / 200% | n/a | | Vesting | 3-Year Cliff Vesting | Annual Ratable Vesting over 3 years (1/3 per year) |

  87. 2025 LTI Program

    All annual LTI awards granted to our executive officers are variable and designed to reward long-term company performance.

  88. 2025 LTI Program

    | 2026 Proxy Statement | -43- |

  89. 2025 LTI Program

    Our LTI program for our executive officers in 2025 consisted of PSUs and RSUs, with 60% of the annual LTI total target grant date value of awards allocated in PSUs (assuming target performance) and 40% allocated in RSUs. The PSUs granted to our executive officers are performance-based and settled in our common stock. The performance conditions applicable to these PSUs are described in further detail below. The RSUs granted to our executive officers are time-based and settled in our common stock. Our annual LTI target grant values are determined based on an executive officer’s individual performance, potential future contributions and market competitiveness, as well as other factors. In determining the LTI target grant value for a year, our CMDC reviews LTI awards made by companies in our peer group and, in certain circumstances, the broader market, and reviews the total compensation level of our executive officers against that of companies in our peer group and, in certain circumstances, the broader market. In general, we place a heavier weight on LTI awards in our executive compensation program to better align the interests of our executives with those of our stockholders. Our established practice is to grant LTI awards annually following the completion of our internal performance reviews of our executive officers as well as our external market review of equity practices of our peer group and the broader market, including data from the Willis Towers Watson survey described later in this document. In 2025, the annual LTI grant values for our NEOs (assuming target performance) were as follows:

  90. 2025 LTI Program

    | Name | LTI Grant Value | | C. Viehbacher | $16,500,000 | | R. Kramer | $3,750,000 | | S. Alexander | $5,250,000 | | P. Singhal | $5,000,000 | | N. Murphy | $5,000,000 |

  91. 2025 LTI Program

    The performance metrics for the 2025 PSUs are a three-year cumulative rTSR and EPS CAGR, each weighted 50%. The 2025 PSUs will vest on the third anniversary of the date of grant, with the number of PSUs earned based on the cumulative rTSR and EPS CAGR metrics. This program is designed to drive our long-term business strategy, is reflective of competitive market practices and aligns with stockholder interests. We believe measuring rTSR and EPS CAGR is critical to see how we perform in comparison to the market. The actual value (if any) of PSUs will not be realized by our NEOs until the three-year period ends and then only if the applicable performance goals are achieved. The table below outlines a summary of PSU awards granted in 2025.

  92. 2025 LTI Program

    | rTSR | Description | | | | | rTSR Comparison Group | Comparator group includes the peer group used for executive compensation benchmarking in 2025 plus the NBI, excluding companies with less than a $5B market capitalization. | | | | | Performance Period | 3 years: 2025-2027 | | | | | Performance Goals & Payouts | | Threshold | Target | Maximum | | | Goal | 25th Percentile | 50th Percentile | 75th Percentile | | | Payout | 25% of Target | 100% of Target | 200% of Target | | | There is no payout for performance below threshold and payouts are capped at 200% of target. Payouts are interpolated for performance between threshold, target and maximum. | | | | | Absolute TSR Cap | In the event our absolute TSR performance over the 2025-2027 period is negative, any payouts under this program will be capped at target, irrespective of rTSR performance. | | | |

  93. 2025 LTI Program

    | EPS CAGR | Description | | | | | Performance Period | 3-year CAGR of EPS Growth: 2025-2027 actual financial results | | | | | Performance Goals & Payouts | Goal payouts based on various levels of EPS CAGR | | | | | | | Threshold | Target | Maximum | | | Payout | 50% of Target | 100% of Target | 200% of Target |

  94. 2025 LTI Program

    We do not disclose our forward-looking EPS CAGR targets, which is consistent with industry practice, because such disclosure could be interpreted as premature guidance and potentially competitively harmful. While we are not disclosing the specific EPS CAGR targets, we believe that achievement of target performance under these awards is challenging but achievable, requiring

  95. 2025 LTI Program

    | 2026 Proxy Statement | -44- |

  96. 2025 LTI Program

    strong operational execution over the three-year performance period. We will continue to disclose performance achievement at the end of the 3-year performance period. The actual value that will be realized from annual PSU awards depends on the degree of achievement of performance goals, with 100% of the PSUs (based on the grant date target value) settled in our common stock based upon achievement of a cumulative three-year rTSR metric and a three-year EPS CAGR. The actual value that will be realized from PSU awards depends on the closing stock price on each of the dates such awards vest. If the vesting price is higher than the grant price, the value of stock that vest will increase and in contrast, if the vesting price is lower than the grant price, the value of stock that vest will be decreased. Our common stock price is influenced by the company’s performance as well as external market factors.

  97. 2024 LTI Program

    2024 LTI Program Our LTI program for our executive officers in 2024 operates with the same design as the 2025 program. We will disclose the details of the 2024 PSU award payout following the completion of the performance period.

  98. 2024 LTI Program

    | rTSR | Description | | | | | rTSR Comparison Group | Comparator group includes the peer group used for executive compensation benchmarking in 2024 plus the NBI, excluding companies with less than a $5B market capitalization. | | | | | Performance Period | 3 years: 2024-2026 | | | | | Performance Goals & Payouts | | Threshold | Target | Maximum | | | Goal | 25th Percentile | 50th Percentile | 75th Percentile | | | Payout | 25% of Target | 100% of Target | 200% of Target | | | There is no payout for performance below threshold and payouts are capped at 200% of target. Payouts are interpolated for performance between threshold, target and maximum. | | | | | Absolute TSR Cap | In the event our absolute TSR performance over the 2024-2026 period is negative, any payouts under this program will be capped at target, irrespective of rTSR performance. | | | |

  99. 2024 LTI Program

    | EPS CAGR | Description | | | | | Performance Period | 3-year CAGR of EPS Growth: 2024-2026 actual financial results | | | | | Performance Goals & Payouts | Goal payouts based on various levels of EPS CAGR | | | | | | | Threshold | Target | Maximum | | | Payout | 50% of Target | 100% of Target | 200% of Target |

  100. 2023 LTI Program

    2023 LTI Program Our LTI program for our executive officers in 2023 consisted of PSUs and RSUs, with the annual LTI total target grant date value split evenly between PSUs and RSUs (assuming target performance on PSUs). The performance metric for the 2023 PSUs was a three-year cumulative rTSR metric. The 2023 PSUs vested on the third anniversary of the date of grant, with the number of PSUs earned based on the cumulative rTSR metric. The actual value of PSUs was not realized by our NEOs until the three-year period ended and then only if the applicable performance goals were achieved. At the beginning of the three-year period for our 2023 PSU awards, our CMDC approved the targets for the metric.

  101. 2023 LTI Program

    | rTSR | Description | | | | | rTSR Comparison Group | Peer group used for executive compensation benchmarking in 2023 | | | | | Performance Period | 3 years: 2023-2025 | | | | | Performance Goals & Payouts | | Threshold | Target | Maximum | | | Goal | 25th Percentile | 55th Percentile | 75th Percentile | | | Payout | 25% of Target | 100% of Target | 200% of Target | | | There is no payout for performance below threshold and payouts are capped at 200% of target. Payouts are interpolated for performance between threshold, target and maximum. | | | | | Absolute TSR Cap | In the event our absolute TSR performance over the 2023-2025 period is negative, any payouts under this program will be capped at target, irrespective of rTSR performance. | | | |

  102. 2023 LTI Program

    | 2026 Proxy Statement | -45- |

  103. 2023 PSU Award Payout

    2023 PSU Award Payout Set forth below is a summary of the performance metrics and weightings that our CMDC established for our 2023 PSU awards and the degree to which we achieved the performance goals for the 2023 PSUs. Relative TSR was below the 25th percentile over the 2023 to 2025 performance period. These PSUs, which comprised 50% of each NEO’s LTI award, did not achieve any payout value, consistent with the program design. This had a significant impact on the realizable pay of our executive officers. It is important to note that the CMDC has not provided any special awards or adjustments to offset these results further demonstrating our commitment to pay outcomes under our pay-for-performance programs.

  104. 2023 PSU Payout Table

    2023 PSU Payout Table

  105. 2023 PSU Payout Table

    | | | | Performance Target | | | | | | Performance Metrics | Performance Period | Threshold | Target | Max | Results | Weight | Payout | | rTSR | 2023-2025 | 25th Percentile 25% of Target | 55th Percentile 100% of Target | 75th Percentile 200% of Target | 13th Percentile | 100% | 0% | | 2023 PSU Multiplier | | | | | | | 0% |

  106. Looking Ahead: 2026 LTI Program

    Looking Ahead: 2026 LTI Program To further strengthen the LTI program’s alignment to achieving Biogen’s long-term goals and ensure that the program targets are set with the rigor our stockholders expect, we will be implementing the following changes in 2026:

  107. Looking Ahead: 2026 LTI Program

    | What We Changed | Why It Matters | | ✓ Added a 25% pipeline milestone metric to rebalance metric weightings: 50% rTSR / 25% Pipeline / 25% 3-yr EPS CAGR ✓ Increased rTSR target from the 50th to 55th percentile | ✓ Strengthens differentiation, emphasizes R&D value creation, and supports long-term stockholder return |

  108. Role of the Independent Compensation Consultant

    Role of the Independent Compensation Consultant The CMDC believes that independent advice is important in developing and overseeing our executive compensation programs. For 2025, Pay Governance was the CMDC’s independent compensation consultant. Pay Governance did not provide any other services to Biogen and engaged in other matters as needed and as directed solely by the CMDC. Reporting directly to the CMDC, the CMDC’s independent compensation consultant provided guidance on trends in CEO, executive officer and non-employee director compensation, the development of specific executive compensation programs and the composition of the company’s compensation peer group used for market comparisons. Additionally, the compensation consultant prepared a comprehensive report on CEO pay that compares each element of our CEO’s compensation to that of CEOs at companies in our peer group. Using this and other similar information, the CMDC recommends, and our Board approves, the elements and target levels of our CEO’s compensation and the CMDC approves the elements and target levels of compensation for our other executive officers. The CMDC assesses the compensation consultant’s independence annually and, in accordance with applicable SEC and Nasdaq rules, confirmed in December 2025 that the consultant’s work did not raise any conflicts of interest and remains independent under applicable rules.

  109. Role of the Independent Compensation Consultant

    | 2026 Proxy Statement | -46- |

  110. Role of our CEO

    To understand the external market competitiveness of the compensation for our NEOs, our CEO and the CMDC review a report analyzing publicly available information and surveys prepared by our internal compensation group and reviewed by the independent compensation consultant. The report compares the compensation of each NEO, other than our CEO, to data available for comparable positions at companies in our peer group and, in certain circumstances, the broader market, by compensation element (please see “External Market Competitiveness and Peer Group” below for further details). The CMDC considers all of the information presented, discusses the recommendations with our CEO and with the independent compensation consultant and applies its judgment to determine the elements of compensation and target compensation levels for each NEO, other than the CEO. Our CEO also provides a self-assessment of his achievements for the prior year. The CMDC reviews and considers this in analyzing the CEO’s performance and in recommending the compensation of our CEO for approval by our Board. Our CEO does not participate in any deliberations regarding his own compensation.

  111. External Market Competitiveness and Peer Group

    External Market Competitiveness and Peer Group We consider market practices and trends when determining executive compensation levels and compensation program design at Biogen. We review external market practices as a reference point to assist us in providing programs designed to attract, retain and inspire extraordinary talent. The CMDC also uses peer group and other market data to provide context for its executive compensation decision-making. Each year the CMDC’s independent compensation consultant reviews the external market data and evaluates the composition of our peer group for appropriateness. The CMDC reviews the information provided from internal sources as well as the information provided by the CMDC’s independent compensation consultant to select our peer group based on comparable companies that approximate (1) our scope of business, including revenue and market capitalization, (2) our global geographical reach, (3) our research-based business with multiple marketed products and (4) a comparable pool of talent for which we compete. The peer group used for setting 2025 target compensation levels and making related compensation decisions for the NEOs consisted of the biotechnology and pharmaceutical companies listed below, as we compete for executive talent with companies in these sectors. This peer group was determined by the CMDC in September 2024 for setting 2025 pay based on an in-depth review by its independent compensation consultant, which included an assessment of potential comparators to evaluate the degree to which the current peers are generally reflective of Biogen’s profile in terms of valuation, size, maturity, global scale and complexity. The assessment also included an examination of the broader marketplace to identify appropriate and relevant removals and/or additions to the peer group. The peer group used for 2025 was unchanged from 2024, except for the removal of Seagen Inc. following its acquisition by Pfizer Inc. in December 2023.

  112. Looking Ahead: 2026 Peers

    Looking Ahead: 2026 Peers In response to stockholder and proxy advisory firm engagement, the CMDC, in partnership with our independent advisor, reviewed the peer group in October 2025. At that time, it was decided to remove Eli Lilly, AbbVie and Merck and add BeOne Medicines to align our peer group closer to Biogen’s size, revenue, and market cap. This updated peer group will be utilized in setting 2026 compensation decisions.

  113. Looking Ahead: 2026 Peers

    | What We Changed | Why It Matters | | ✓ Rebalanced peer group to better reflect Biogen’s size, revenue, and market cap by removing Eli Lilly, AbbVie and Merck while adding BeOne Medicines. | ✓ Improves comparability and rigor in benchmarking. |

  114. Looking Ahead: 2026 Peers

    For each of the companies in our peer group, when available, we analyze the company’s CD&A and other data publicly filed during the prior year to identify the executives at such companies whose positions are comparable to those held by our NEOs, including our CEO. We then compile and analyze the data for each comparable position. Our competitive analysis includes the structure and design of the executive compensation programs as well as the targeted value of the compensation under these programs. For our Executive Committee, other than our CEO, we may supplement the data from our peer group with published compensation surveys. For 2025, consistent with past years, we used the Willis Towers Watson survey. We chose the Willis Towers Watson survey because of the number of companies in our peer group that participate in it, the number of positions reported by the survey that continue to be comparable to our NEO positions and the high standards under which we understand the survey is conducted (including data collection and analysis methodologies). All of the companies in our peer group are represented in a special cross-section of the Willis Towers Watson survey focused on our peer group. This survey data includes other relevant companies in the biotech and pharmaceutical industry with which we compete for talent. A summary of the process our CMDC follows in setting compensation is described below:

  115. Post-Termination Compensation and Benefits

    Post-Termination Compensation and Benefits We provide severance benefits to all of our executive officers if their employment is terminated without cause or in certain other circumstances. The terms of these arrangements and the amounts payable under them are described below for each NEO under the heading “Potential Payments Upon Termination or Change in Control.” We provide these benefits because we believe that severance protection is necessary to help our executives maintain their focus on the best interests of the company when providing advice to the company and when making strategic decisions about a potential corporate transaction or change in control, and further encourages effective leadership in the closing and integration of significant transactions affecting the company.

  116. Timing of Equity Awards

    Timing of Equity Awards While we do not have a specific policy on the timing of equity awards to our NEOs, our longstanding practice has been to consider and grant annual equity awards to our NEOs at our February Board meeting. We also occasionally grant new hire or other special grants in connection with recruitment of executive officers or other business needs. We do not take material nonpublic information into account when determining the timing and terms of awards nor do we time the disclosure of material nonpublic information for the purpose of affecting the value of executive compensation. We do not currently grant awards of stock options, stock appreciation rights or similar option-like awards to our NEOs, but the Board has done so in the past (including in connection with the recruitment and hiring of our CEO) and reserves the right to grant such awards in the future.

  117. Summary Compensation Table

    Summary Compensation Table The following table shows the compensation paid to or earned by our NEOs during the years ended December 31, 2025, December 31, 2024, and December 31, 2023, for the year(s) in which they were a NEO under applicable SEC rules.

  118. Summary Compensation Table

    | Name and Principal Position (a) | Year (b) | Salary (c) | Bonus(1) (d) | Stock Awards(2) (e) | Non-Equity Incentive Plan Compensation(3) (f) | Change in Pension Value and Nonqualified Deferred Compensation Earnings(4) (g) | All Other Compensation(5) (h) | Total (i) | | Christopher A. Viehbacher President and Chief Executive Officer | 2025 | $1,727,885 | — | $18,368,875 | $3,190,875 | — | $358,369 | $23,646,004 | | | 2024 | $1,600,000 | — | $18,010,911 | $4,308,480 | $3,573 | $243,701 | $24,166,665 | | | 2023 | $1,600,000 | — | — | $2,376,000 | $39 | $93,874 | $4,069,913 | | Robin C. Kramer(6) Executive Vice President and Chief Financial Officer | 2025 | $759,617 | — | $4,173,781 | $788,252 | — | $84,934 | $5,806,584 | | Susan H. Alexander Executive Vice President, Chief Legal Officer | 2025 | $1,028,111 | — | $5,845,129 | $1,062,219 | $37,718 | $159,340 | $8,132,517 | | | 2024 | $954,192 | — | $3,879,219 | $1,516,537 | — | $155,881 | $6,505,829 | | | 2023 | $924,417 | — | $4,600,947 | $846,611 | $148,759 | $183,118 | $6,703,852 | | Priya A. Singhal Head of Development | 2025 | $929,712 | $898 | $5,566,081 | $950,833 | — | $123,863 | $7,571,387 | | | 2024 | $816,346 | — | $4,433,862 | $1,020,938 | $2,110 | $114,407 | $6,387,663 | | Nicole C. Murphy Head of Pharmaceutical Operations and Technology | 2025 | $909,109 | — | $5,566,081 | $977,828 | — | $122,487 | $7,575,505 | | | 2024 | $764,567 | — | $3,879,219 | $999,034 | — | $97,539 | $5,740,359 | | | 2023 | $670,642 | — | $4,268,453 | $676,603 | — | $98,621 | $5,714,319 | | Michael R. McDonnell(7) Former Executive Vice President and Chief Financial Officer | 2025 | $226,895 | — | — | — | — | $43,955 | $270,850 | | | 2024 | $992,531 | — | $4,433,862 | $1,211,989 | $1,056 | $187,296 | $6,826,734 | | | 2023 | $945,268 | — | $4,960,629 | $1,129,183 | $837 | $131,684 | $7,167,601 |

  119. Summary Compensation Table

    Notes to the Summary Compensation Table

  120. Summary Compensation Table

    | (1) The amount in column (d) reflects a special service-based recognition award provided to Dr. Singhal in 2025. |

  121. Summary Compensation Table

    | (2) The amounts in column (e) reflect the grant date fair value, computed in accordance with ASC 718, for RSUs and PSUs granted during 2025, 2024 and 2023, excluding the effect of estimated forfeitures. The 2025 and 2024 amounts include rTSR PSUs, EPS CAGR PSUs and RSUs. Under the former LTI design, a portion of PSUs were settled in cash. The cash portion of PSUs are included in the year when the applicable performance goals were set and the fair value of the PSUs was determinable. For NEOs, except Mr. Viehbacher, the 2023 amounts include rTSR PSUs, RSUs, and one-third of the cash-settled PSUs from 2021, which is the tranche of the award for which performance goals were set in 2023 relating to the 2023 performance period. The grant date fair value for rTSR PSU awards was determined as of the date of grant using a lattice model with a Monte Carlo simulation based on the probable outcome of applicable performance conditions. The grant date fair value for RSU and EPS CAGR PSU awards was determined by multiplying the number of stock subject to the award (assuming target performance for such PSUs) by the closing price of the company’s common stock on the grant date. |

  122. Summary Compensation Table

    | | 2025 | | 2024 | | 2023 | | | Executive Officer | Target Payout | Maximum Payout | Target Payout | Maximum Payout | Target Payout | Maximum Payout | | Mr. Viehbacher | $11,768,602 | $23,537,204 | $11,510,318 | $23,020,635 | — | — | | Ms. Kramer | $2,673,913 | $5,347,826 | — | — | — | — | | Ms. Alexander | $3,745,172 | $7,490,343 | $2,479,276 | $4,958,552 | $2,725,541 | $5,451,081 | | Dr. Singhal | $3,565,783 | $7,131,565 | $2,834,271 | $5,668,542 | — | — | | Ms. Murphy | $3,565,783 | $7,131,565 | $2,479,276 | $4,958,552 | $2,468,691 | $4,937,382 | | Mr. McDonnell | — | — | $2,834,271 | $5,668,542 | $2,961,052 | $5,922,104 |

  123. Summary Compensation Table

    | (3) The amounts in column (f) reflect actual non-equity incentive plan compensation paid under our STI program for the applicable year. |

  124. Summary Compensation Table

    | (4) The amounts in column (g) reflect earnings in the SSP that are in excess of 120% of the applicable federal long-term rate. The federal long-term rates applied in this calculation are 5.44%, 5.32% and 5.33% for 2025, 2024 and 2023, respectively. The SSP is described under the heading “2025 Non-Qualified Deferred Compensation” on page 56. |

  125. Summary Compensation Table

    | 2026 Proxy Statement | -52- |

  126. Summary Compensation Table

    | (5) The amounts in column (h) for 2025 reflect the following: |

  127. Summary Compensation Table

    | Executive Officer | Company Matching Contribution to 401(k) Plan Account | Company Contribution to SSP Account | Personal Health and Financial Planning* | Value of Company-Paid Life Insurance Premiums | | Mr. Viehbacher | $21,000 | $336,278 | — | $1,091 | | Ms. Kramer | $21,000 | $55,766 | $6,804 | $1,364 | | Ms. Alexander | $21,000 | $128,851 | $7,400 | $2,089 | | Dr. Singhal | $21,000 | $92,802 | $8,261 | $1,800 | | Ms. Murphy | $21,000 | $89,816 | $9,977 | $1,694 | | Mr. McDonnell | $21,000 | $13,819 | $7,500 | $1,636 |

  128. Summary Compensation Table

    | * Represents reimbursements of expenses relating to tax, financial and estate planning and executive physicals as described under the heading “Executive Physicals, Tax Preparation, Financial and Estate Planning” above. The amount for Dr. Singhal includes the 2025 benefit of $4,700 and reimbursement in 2025 of the 2024 benefit of $3,561. The amount for Ms. Murphy includes the 2025 benefit of $2,477 and reimbursement in 2025 of the 2024 benefit of $7,500. |

  129. Summary Compensation Table

    | (6) Ms. Kramer was promoted to the role of Executive Vice President and Chief Financial Officer effective March 1, 2025. Previously, Ms. Kramer served as Biogen’s Senior Vice President and Chief Accounting Officer. Amounts reflect totals received in 2025 for service in the two roles. |

  130. Summary Compensation Table

    | (7) Mr. McDonnell ceased to be our Executive Vice President and Chief Financial Officer and retired on March 1, 2025. Mr. McDonnell’s base salary was prorated for the period of the year during which he was employed by the company. Mr. McDonnell was not eligible to receive a bonus under our 2025 STI program, and, upon his retirement, any unvested equity holdings were forfeited consistent with the 2017 Omnibus Equity Plan and 2024 Omnibus Equity Plan. |

  131. 2025 Grants of Plan-Based Awards

    2025 Grants of Plan-Based Awards The following table shows additional information regarding all grants of plan-based awards made to our NEOs for the year ended December 31, 2025, except Mr. McDonnell who retired from the company on March 1, 2025, and was not eligible to receive a bonus under our 2025 STI program and did not receive grants of PSUs or RSUs in 2025.

  132. 2025 Grants of Plan-Based Awards

    | | | | Estimated Future Payouts Under Non-Equity Incentive Plan Awards(1) | | | Estimated Future Payouts Under Equity Incentive Plan Awards (#)(1) | | | All Other Stock Awards: Number of Shares or Units (#) | All other option awards: Number of securities underlying options (#) | Grant Date Fair Value of Stock Awards(2) | | Name | Grant Date | | Threshold | Target | Maximum | Threshold | Target | Maximum | | | | | (a) | (b) | Notes | (c) | (d) | (e) | (f) | (g) | (h) | (i) | (j) | (k) | | Christopher A. Viehbacher | 02/06/2025 | (3) | $628,125 | $2,512,500 | $5,653,125 | — | — | — | — | — | — | | | 02/06/2025 | (4) | — | — | — | 8,693 | 34,770 | 69,540 | — | — | $6,818,397 | | | 02/06/2025 | (5) | — | — | — | 17,385 | 34,770 | 69,540 | — | — | $4,950,205 | | | 02/06/2025 | (6) | — | — | — | — | — | — | 46,360 | — | $6,600,273 | | Robin C. Kramer | 02/06/2025 | (3) | $141,062 | $564,247 | $1,269,555 | — | — | — | — | — | — | | | 02/06/2025 | (4) | — | — | — | 1,975 | 7,900 | 15,800 | — | — | $1,549,190 | | | 02/06/2025 | (5) | — | — | — | 3,950 | 7,900 | 15,800 | — | — | $1,124,723 | | | 02/06/2025 | (6) | — | — | — | — | — | — | 10,535 | — | $1,499,868 | | Susan H. Alexander | 02/06/2025 | (3) | $199,141 | $796,565 | $1,792,271 | — | — | — | — | — | — | | | 02/06/2025 | (4) | — | — | — | 2,766 | 11,065 | 22,130 | — | — | $2,169,847 | | | 02/06/2025 | (5) | — | — | — | 5,533 | 11,065 | 22,130 | — | — | $1,575,324 | | | 02/06/2025 | (6) | — | — | — | — | — | — | 14,750 | — | $2,099,958 | | Priya A. Singhal | 02/06/2025 | (3) | $170,156 | $680,625 | $1,531,406 | — | — | — | — | — | — | | | 02/06/2025 | (4) | — | — | — | 2,634 | 10,535 | 21,070 | — | — | $2,065,914 | | | 02/06/2025 | (5) | — | — | — | 5,268 | 10,535 | 21,070 | — | — | $1,499,868 | | | 02/06/2025 | (6) | — | — | — | — | — | — | 14,050 | — | $2,000,299 | | Nicole C. Murphy | 02/06/2025 | (3) | $167,379 | $669,516 | $1,506,411 | — | — | — | — | — | — | | | 02/06/2025 | (4) | — | — | — | 2,634 | 10,535 | 21,070 | — | — | $2,065,914 | | | 02/06/2025 | (5) | — | — | — | 5,268 | 10,535 | 21,070 | — | — | $1,499,868 | | | 02/06/2025 | (6) | — | — | — | — | — | — | 14,050 | — | $2,000,299 |

  133. 2025 Grants of Plan-Based Awards

    Notes to the 2025 Grants of Plan-Based Awards Table

  134. 2025 Grants of Plan-Based Awards

    | (1) Reflects the potential future payouts of awards granted in 2025 under our 2025 STI program and our LTI program as of the respective grant dates. |

  135. 2025 Grants of Plan-Based Awards

    | (2) Represents the grant date fair value of PSUs and RSUs, as applicable, computed in accordance with ASC 718, excluding the effect of estimated forfeitures. The grant date fair value for rTSR PSU awards is determined as of the date of grant using a lattice model with a Monte Carlo |

  136. 2025 Grants of Plan-Based Awards

    | 2026 Proxy Statement | -53- |

  137. 2025 Grants of Plan-Based Awards

    | simulation based on the probable outcome of applicable performance conditions. In addition, the grant date fair value for EPS CAGR PSUs and RSUs is determined as of the date of grant using the closing price of our common stock on the grant date. The assumptions used to calculate the grant date fair value of stock awards are included in footnote 16 of our 2025 Annual Report on Form 10-K. The maximum payouts for these awards are included in the footnotes following the Summary Compensation Table above. |

  138. 2025 Grants of Plan-Based Awards

    | (3) These amounts relate to our 2025 STI program. The amounts shown in column (d) represent the 2025 target payout amount based on the target percentage applied to each NEO’s base salary as of December 31, 2025. For 2025, the bonus targets were 150% of base salary for Mr. Viehbacher, 80% of base salary for Ms. Kramer and Ms. Alexander and 75% of base salary for Ms. Murphy and Dr. Singhal. For Ms. Kramer, the amounts reported are based on a prorated bonus target for 2025 based on the March 1, 2025, promotion date. The amounts in column (c), (d) and (e) represent a payment if the Company Multiplier and the Individual Multiplier were each 50%, 100% and 150%, respectively. Actual amounts paid to each NEO under our 2025 STI program are included in the “Non-Equity Incentive Plan Compensation” column of the Summary Compensation Table above. |

  139. 2025 Grants of Plan-Based Awards

    | (4) These amounts relate to the annual grant of rTSR PSUs. The rTSR PSUs are earned based on three-year cumulative rTSR performance after the end of a three-year performance period (1/1/25-12/31/27) and vest on the third anniversary of the date of grant. The number and value shown in columns (g) and (k), respectively, assume target performance results. For additional information on the rTSR PSU awards, please see “Long-Term Incentives” on page 43. |

  140. 2025 Grants of Plan-Based Awards

    | (5) These amounts relate to the annual grant of EPS CAGR PSUs. The EPS CAGR PSUs are earned based on three-year compound annual growth EPS performance after the end of a three-year performance period (1/1/25-12/31/27) and vest on the third anniversary of the date of grant. The number and value shown in columns (g) and (k), respectively, assume target performance results. For additional information on the EPS CAGR PSU awards, please see “Long-Term Incentives” on page 43. |

  141. 2025 Grants of Plan-Based Awards

    | (6) These amounts relate to the annual grant of RSUs. The RSU awards will be eligible to vest in approximately equal annual installments on the first, second and third anniversaries of the grant date. |

  142. 2025 Grants of Plan-Based Awards

    | 2026 Proxy Statement | -54- |

  143. Outstanding Equity Awards at 2025 Fiscal Year-End

    Outstanding Equity Awards at 2025 Fiscal Year-End The following table summarizes the equity awards that were outstanding as of December 31, 2025, for each of our NEOs.

  144. Outstanding Equity Awards at 2025 Fiscal Year-End

    | | | | Option Awards | | | | Stock Awards | | | | | | | | Number of Securities Underlying Unexercised Options Exercisable | Number of Securities Underlying Unexercised Options Unexercisable | Option Exercise Price | Option Expiration Date | Number of Shares or Units of Stock That Have Not Vested | Market Value of Shares or Units of Stock That Have Not Vested(1) | Equity Incentive Plan Awards | | | Name | Grant Date | | | | | | | | Number of Unearned Shares or Units That Have Not Vested | Market Value of Unearned Shares or Units That Have Not Vested(1) | | (a) | (b) | Notes | (c) | (d) | (e) | (f) | (g) | (h) | (i) | (j) | | Christopher A. Viehbacher | 12/1/2022 | (2) | 80,522 | — | $301.85 | 12/1/2032 | — | — | — | — | | | 2/7/2024 | (3) | — | — | — | — | — | — | 5,066 | $891,565 | | | 2/7/2024 | (4) | — | — | — | — | — | — | 10,133 | $1,783,307 | | | 2/7/2024 | (5) | — | — | — | — | 18,017 | $3,170,812 | — | — | | | 2/6/2025 | (3) | — | — | — | — | — | — | 34,770 | $6,119,172 | | | 2/6/2025 | (4) | — | — | — | — | — | — | 34,770 | $6,119,172 | | | 2/6/2025 | (5) | — | — | — | — | 46,360 | $8,158,896 | — | — | | Robin C. Kramer | 2/8/2023 | (3) | — | — | — | — | — | — | — | — | | | 2/8/2023 | (5) | — | — | — | — | 789 | $138,856 | — | — | | | 2/7/2024 | (3) | — | — | — | — | — | — | 395 | $69,516 | | | 2/7/2024 | (4) | — | — | — | — | — | — | 790 | $139,032 | | | 2/7/2024 | (5) | — | — | — | — | 1,407 | $247,618 | — | — | | | 2/6/2025 | (3) | — | — | — | — | — | — | 7,900 | $1,390,321 | | | 2/6/2025 | (4) | — | — | — | — | — | — | 7,900 | $1,390,321 | | | 2/6/2025 | (5) | — | — | — | — | 10,535 | $1,854,055 | — | — | | Susan H. Alexander | 2/8/2023 | (3) | — | — | — | — | — | — | — | — | | | 2/8/2023 | (5) | — | — | — | — | 2,190 | $385,418 | — | — | | | 2/7/2024 | (3) | — | — | — | — | — | — | 1,091 | $192,005 | | | 2/7/2024 | (4) | — | — | — | — | — | — | 2,183 | $384,186 | | | 2/7/2024 | (5) | — | — | — | — | 3,880 | $682,841 | — | — | | | 2/6/2025 | (3) | — | — | — | — | — | — | 11,065 | $1,947,329 | | | 2/6/2025 | (4) | — | — | — | — | — | — | 11,065 | $1,947,329 | | | 2/6/2025 | (5) | — | — | — | — | 14,750 | $2,595,853 | — | — | | Priya A. Singhal | 2/8/2023 | (3) | — | — | — | — | — | — | — | — | | | 2/8/2023 | (5) | — | — | — | — | 1,829 | $321,886 | — | — | | | 2/7/2024 | (3) | — | — | — | — | — | — | 1,248 | $219,636 | | | 2/7/2024 | (4) | — | — | — | — | — | — | 2,495 | $439,095 | | | 2/7/2024 | (5) | — | — | — | — | 4,434 | $780,340 | — | — | | | 2/6/2025 | (3) | — | — | — | — | — | — | 10,535 | $1,854,055 | | | 2/6/2025 | (4) | — | — | — | — | — | — | 10,535 | $1,854,055 | | | 2/6/2025 | (5) | — | — | — | — | 14,050 | $2,472,660 | — | — | | Nicole C. Murphy | 2/8/2023 | (3) | — | — | — | — | — | — | — | — | | | 2/8/2023 | (5) | — | — | — | — | 2,102 | $369,931 | — | — | | | 2/7/2024 | (3) | — | — | — | — | — | — | 1,091 | $192,005 | | | 2/7/2024 | (4) | — | — | — | — | — | — | 2,183 | $384,186 | | | 2/7/2024 | (5) | — | — | — | — | 3,880 | $682,841 | — | — | | | 2/6/2025 | (3) | — | — | — | — | — | — | 10,535 | $1,854,055 | | | 2/6/2025 | (4) | — | — | — | — | — | — | 10,535 | $1,854,055 | | | 2/6/2025 | (5) | — | — | — | — | 14,050 | $2,472,660 | — | — | | Michael R. McDonnell(6) | — | — | — | — | — | — | — | — | — | — |

  145. Outstanding Equity Awards at 2025 Fiscal Year-End

    Notes to the Outstanding Equity Awards at 2025 Fiscal Year-End Table

  146. Outstanding Equity Awards at 2025 Fiscal Year-End

    | (1) The market value of awards is based on the closing price of our stock on December 31, 2025 ($175.99) as reported on Nasdaq. |

  147. Outstanding Equity Awards at 2025 Fiscal Year-End

    | (2) Stock options were granted to Mr. Viehbacher in 2022. They vested and became exercisable in approximately equal annual installments on the first, second and third anniversaries of the grant date. |

  148. Outstanding Equity Awards at 2025 Fiscal Year-End

    | (3) rTSR PSUs were granted in 2023, 2024 and 2025. Actual rTSR PSUs are earned based on three-year cumulative rTSR performance after the end of a three-year performance period (1/1/23-12/31/25, 1/1/24-12/31/26 and 1/1/25-12/31/27, respectively) and vest on the third anniversary of the date of grant. For 2023 rTSR PSUs, the numbers and values shown in columns (g) and (h), respectively, reflect no earned PSUs based on actual rTSR performance. For 2024 rTSR PSUs, the numbers and values shown in columns (i) and (j), respectively, assume threshold |

  149. Outstanding Equity Awards at 2025 Fiscal Year-End

    | 2026 Proxy Statement | -55- |

  150. Outstanding Equity Awards at 2025 Fiscal Year-End

    | performance results. For 2025 rTSR PSUs, the numbers and values shown in columns (i) and (j), respectively, assume target performance results. For additional information on the rTSR PSU awards, please see “Long-Term Incentives” on page 43. |

  151. Outstanding Equity Awards at 2025 Fiscal Year-End

    | (4) EPS CAGR PSUs were granted in 2024 and 2025. Actual EPS CAGR PSUs are earned based on three-year cumulative EPS performance after the end of a three-year performance period (1/1/24-12/31/26 and 1/1/25-12/31/27, respectively) and vest on the third anniversary of grant. For 2024 EPS CAGR PSUs, the numbers and values shown in columns (i) and (j), respectively, assume threshold performance results. For 2025 EPS CAGR PSUs, the numbers and values shown in columns (i) and (j), respectively, assume target performance results. For additional information on the EPS CAGR PSU awards, please see “Long-Term Incentives” on page 43. |

  152. Outstanding Equity Awards at 2025 Fiscal Year-End

    | (5) RSU awards were granted in 2023, 2024 and 2025. They vest in three annual installments beginning on the first anniversary of the grant date. |

  153. Outstanding Equity Awards at 2025 Fiscal Year-End

    | (6) Mr. McDonnell ceased to be our Executive Vice President and Chief Financial Officer and retired on March 1, 2025. Upon his retirement, any unvested equity holdings were forfeited consistent with the 2017 Omnibus Equity Plan and 2024 Omnibus Equity Plan. Mr. McDonnell did not hold any Biogen equity awards as of December 31, 2025. |

  154. 2025 Option Exercises and Stock Vested

    2025 Option Exercises and Stock Vested The following table shows information regarding the exercise of stock options and the vesting of stock awards for each NEO during the year ended December 31, 2025. No NEO exercised stock options during 2025.

  155. 2025 Option Exercises and Stock Vested

    | Name | Number of Shares Acquired on Vesting(1) | Value Realized on Vesting(2) | | Christopher A. Viehbacher | 16,048 | $2,524,852 | | Robin C. Kramer | 2,325 | $329,631 | | Susan H. Alexander | 6,705 | $950,816 | | Priya A. Singhal | 6,925 | $969,769 | | Nicole C. Murphy | 6,314 | $895,188 | | Michael R. McDonnell | 7,808 | $1,107,537 |

  156. 2025 Option Exercises and Stock Vested

    Notes to the 2025 Option Exercises and Stock Vested Table

  157. 2025 Option Exercises and Stock Vested

    | (1) No shares vested under PSU programs in 2025. The number of our actual common stock acquired on vesting of RSUs in 2025, after stock was withheld to pay the minimum withholding of taxes, was as follows: |

  158. 2025 Option Exercises and Stock Vested

    | Name | Net Shares Acquired | | Christopher A. Viehbacher | 9,443 | | Robin C. Kramer | 1,604 | | Susan H. Alexander | 4,664 | | Priya A. Singhal | 4,502 | | Nicole C. Murphy | 4,421 | | Michael R. McDonnell | 4,935 |

  159. 2025 Option Exercises and Stock Vested

    | (2) The value realized for RSUs was calculated by multiplying the closing price of a share of our common stock on the vesting date by the total number of shares that vested on such date. |

  160. 2025 Non-Qualified Deferred Compensation

    2025 Non-Qualified Deferred Compensation The SSP covers our executive officers and other eligible employees in the U.S. Employees whose base salary and annual cash incentives for the year exceed a specified Internal Revenue Service’s limit ($350,000 in 2025) and who receive a company-paid restoration match on the portion of their base salary, annual bonus and cash payments in respect of CSPUs and cash-settled PSUs, as applicable, that exceeds this limit; the restoration match equals 6% of this excess compensation. The restoration match feature is intended to provide the amount of matching employer contributions that the participant would otherwise have been eligible to receive under our 401(k) plan but for the limit imposed by Section 401(a)(17) of the Internal Revenue Code ($350,000 for 2025). In addition, eligible employees may make voluntary contributions of up to 80% of their base salary and 100% of their annual bonus and cash payments in respect of CSPUs and cash-settled PSUs, as applicable, to the SSP. The company does not match participants’ voluntary contributions to the SSP. The SSP provides for immediate vesting of the restoration match consistent with our immediate vesting of the company match provided under our 401(k) plan. Notional SSP accounts are maintained for each participant. Accounts include employee and employer contributions and reflect the performance of notional investments selected by the employee or a default investment if the employee does not make a selection. These notional investment options include the mutual funds similar to those offered under our 401(k) plan as well as a fixed rate option which earns a rate of return determined each year by the company’s retirement committee. For contributions to the SSP fixed rate option in 2025, this rate of return was set at 5.5%. Contributions to the fixed rate option continue to earn interest at the rate of return that was in effect during the year of contribution. The excess of the interest rate applicable to the fixed rate option above 120% of the applicable federal long-term rate (compounded quarterly) earned by our NEOs during 2025 is shown in the Summary Compensation Table. We fund the SSP liabilities through COLI, which we purchase with the written consent of SSP participants, and investments in mutual funds. We believe that the COLI policies and mutual funds will be sufficient to cover plan liabilities through the projected payout date so the plan will not require direct funding by the company. Upon enrollment in the SSP, a participant must

  161. 2025 Non-Qualified Deferred Compensation

    | 2026 Proxy Statement | -56- |

  162. 2025 Non-Qualified Deferred Compensation

    elect when and how distributions will be made from the participant’s account. Distributions can be made upon termination of the participant’s employment, either in a lump sum or up to 15 annual installments, or at a specified future date while the participant is still employed (an “in-service” distribution), either in a lump sum or up to 5 annual installments. Further, upon enrollment, a participant must also elect a distribution method upon death or a CIC of the Company, which can either be a lump sum payment or, if different, the method selected for payment upon termination of employment. The following table shows a summary of all contributions to, earnings on, and distributions received from, the SSP for each of our NEOs for the year ended December 31, 2025. The account balances as of year-end include all contributions and interest amounts earned by our NEOs through the end of 2025.

  163. 2025 Non-Qualified Deferred Compensation

    | Name | Executive Contributions in Last Fiscal Year(1) | Company Contributions in Last Fiscal Year(2) | Aggregate Earnings in Last Fiscal Year(3) | Aggregate Distributions in Last Fiscal Year | Aggregate Balance at Last Fiscal Year-End(4) | | Christopher A. Viehbacher | $3,188,725 | $336,278 | $1,017,722 | — | $7,066,006 | | Robin C. Kramer | $433,133 | $55,766 | $86,745 | — | $1,885,189 | | Susan H. Alexander | — | $128,851 | $914,255 | — | $17,446,815 | | Priya A. Singhal | $390,130 | $92,802 | $94,985 | — | $1,392,647 | | Nicole C. Murphy | — | $89,816 | $11,931 | — | $336,428 | | Michael R. McDonnell | — | $13,819 | $15,866 | ($444,326) | — |

  164. 2025 Non-Qualified Deferred Compensation

    Notes to the 2025 Non-Qualified Deferred Compensation Table

  165. 2025 Non-Qualified Deferred Compensation

    | (1) The amounts in this column are also included, in part, in columns (c) and/or (g) of the Summary Compensation Table and represent deferral of salary and deferral of payments under our 2025 STI program, respectively. |

  166. 2025 Non-Qualified Deferred Compensation

    | (2) The amounts in this column are also included in column (h) of the Summary Compensation Table for 2025 as company contributions to the SSP. |

  167. 2025 Non-Qualified Deferred Compensation

    | (3) Earnings in excess of 120% of the applicable federal long-term rate are reported in column (h) of the Summary Compensation Table for 2025 for Ms. Alexander ($37,718). |

  168. 2025 Non-Qualified Deferred Compensation

    | (4) The following table lists the compensation deferrals during 2024 and 2023 by our NEOs, as reported, where applicable, in the Proxy Statement for our 2025 and 2024 Annual Meetings: |

  169. 2025 Non-Qualified Deferred Compensation

    | | Amounts Previously Reported as Deferred | | | Name | 2024* | 2023* | | Christopher A. Viehbacher | $1,823,200 | $141,539 | | Robin C. Kramer | — | — | | Susan H. Alexander | — | $1,137,552 | | Priya A. Singhal | $287,925 | — | | Nicole C. Murphy | — | — | | Michael R. McDonnell | — | — |

  170. 2025 Non-Qualified Deferred Compensation

    * This column also includes company contributions and compensation earned and deferred in prior years, which was disclosed in our prior Proxy Statements where applicable, together with earnings on these amounts.

  171. Potential Payments Upon Termination or Change in Control

    Potential Payments Upon Termination or Change in Control

  172. Potential Post-Termination Payments Table

    | (2) At December 31, 2025, Ms. Alexander was eligible for potential payments upon retirement. Based on years of service, Ms. Alexander was eligible for accelerated vesting on 100% of outstanding equity awards as of December 31, 2025. Any unvested PSU awards would, subject to the achievement of any applicable performance goals, remain outstanding and eligible to be earned and vest in accordance with the terms of such awards based on actual performance as to 100% of the earned PSUs. The amount listed in column (b) is the estimated value of 100% of all unvested awards held by Ms. Alexander, based on actual performance estimated as of December 31, 2025, for unearned performance-based awards. Beginning with 2022 grants, if retirement occurs within the same calendar year of grant, only one-third of the grant will vest. |

  173. CEO Pay Ratio

    CEO Pay Ratio We believe executive pay must be internally consistent and equitable to motivate our employees to create stockholder value, and we are committed to internal pay equity. As discussed earlier in this Proxy Statement, our compensation programs are designed to drive the creation of long-term stockholder value by delivering performance-based compensation. We invest in our employees at all levels in the company by rewarding performance that balances risk and reward, empowering professional growth and development and offering affordable benefits and programs that meet the diverse needs of our employees. We believe strongly in pay-for-performance, and all of our employees are eligible to participate in our STI program, our LTI programs and our benefit plans. Our STI program incorporates achievement of company, individual and, in some cases, function or region-specific performance goals. Payout levels (as a percentage of target) are based upon employee level and administrative provisions are the same for all participants globally. Our LTI programs provide different forms of awards depending upon an employee’s level but are otherwise consistent throughout the company. The following is a reasonable estimate, prepared under applicable SEC rules, of the ratio of the annual total compensation of our CEO to the median of the annual total compensation of our other employees. We determined our median employee as of December 31, 2025, based on a consistently applied compensation measure defined as the sum of base salary, target bonus and LTI target value. We annualized pay for employees who commenced employment during 2025. Our median employee is a full-time employee based in the U.S. In December 2025, when we determined the median employee, approximately 56% of our workforce was based in the U.S. with the remaining approximately 44% of our workforce based in the rest of the world. In addition, approximately 98% of our workforce was full-time. For our median employee, annual total compensation was calculated in accordance with the SEC’s rules for the Summary Compensation Table, including salary, bonus, LTI grant date fair value and value of certain benefits provided. For Mr. Viehbacher, who was CEO at the time we identified our median employee, annual total compensation is equal to the amount included in the “Total” column of the Summary Compensation Table, which results in an annual total compensation for 2025 of $23,646,004. The annual total compensation of the median employee, as determined in accordance with the SEC’s rules, for 2025 was $208,335. Based on the foregoing, our estimate of the ratio of the annual total compensation of our CEO to the median of the annual total compensation of our other employees was 113 to 1. Given the different methodologies, estimates, assumptions and exclusions that other public companies use to determine an estimate of their pay ratio, the estimated ratio reported above should not be used as a basis for comparison between companies.

  174. CEO Pay Ratio

    | 2026 Proxy Statement | -61- |

  175. CEO Pay Ratio

    As discussed in our CD&A above, our CMDC has implemented executive compensation programs designed to link a substantial part of our NEOs compensation to financial, strategic and market-based measures and align realizable compensation with stockholder returns. The following table sets forth additional compensation information for our NEOs, calculated in accordance with SEC regulations, for fiscal years 2025, 2024, 2023, 2022 and 2021. Pay versus Performance Tabular Disclosure: The table below contains information about the relationship between compensation actually paid, as computed in accordance with SEC rules, to our CEO and non-CEO NEOs as a group, and our financial performance for the five years 2021 – 2025. The cumulative Total Stockholder Return depicts a hypothetical $100 investment in our common stock on December 31, 2020, and shows the value of that investment over time for each calendar year. A hypothetical $100 investment in the NBI using the same methodology is shown for comparison. The CMDC did not consider the PVP disclosure below in making its pay decisions for any of the fiscal years shown. In addition, the average non-CEO NEO incumbents differ year to year and may comprise different roles with different individual and market-based considerations impacting compensation decisions. Comparing the summary compensation table total average and compensation actually paid average for the non-CEO NEOs year-over-year does not accurately depict changes in these values for the same individuals.

  176. Narrative to Pay versus Performance Table

    Narrative to Pay versus Performance Table For the fiscal year ending December 31, 2025, the most important financial measures we identified for the purposes of the PVP disclosure requirement linking compensation actually paid to our NEOs to company performance are TSR, total revenue and growth product revenue, EPS, and performance against our pipeline milestone metrics. CAP reflects, among other items, adjustments to the fair value of equity awards during the years presented as well as expired and unearned awards. Factors impacting the fair value of equity awards include the price of our common stock at year end, as well as the projected and actual achievement of performance goals under our equity awards. These adjustments contributed significantly to the CAP value reported for each year. LTI awards represent a large percentage of our NEOs’ target compensation. Because the value of our LTI awards is tied to the value of our common stock, rTSR will have a significant influence on the value of such awards and thereafter aligns the value of realizable pay to long-term stockholder value creation. This was demonstrated in both the 2022 and 2023 PSU Programs when rTSR achievement was below the 25th percentile resulting in no payout value, consistent with the program design. This had a significant impact on the realizable pay of our executives. It is important to note that the CMDC has not provided any special awards or adjustments to offset these results, further demonstrating our commitment to pay outcomes under our pay for performance programs. Revenue and EPS were significant components in the STI program scorecard for each of the presented years and are important measures of our company’s financial performance. Net income is included for disclosure requirements, but there is no relationship between net income and CAP in our incentive plans except where it applies to EPS. Successfully advancing therapies through our pipeline and performing against our pipeline milestone metrics are key value drivers for our company’s long-term growth. Pipeline performance has also driven significant changes in the price of our common stock, and therefore impacts the CAP calculation. We recognize our pipeline as a critical area of focus for our strategy and the long-term success of our company.

  177. Narrative to Pay versus Performance Table

    | Fiscal Year | SCT Total for CEO: C. Viehbacher (1) | SCT Total for Former CEO: M. Vounatsos (1) | Compensation Actually Paid to CEO (2) | Compensation Actually Paid to Former CEO (2) | Average SCT Total for Other NEOs (3) | Average Compensation Actually Paid for Other NEOs (3) | Value of $100 Initial Fixed Investment Based on TSR (4) | Value of $100 Initial Fixed Investment Based on Nasdaq Biotech Index TSR (4) | Net Income ($M) | Company Selected Measure: Revenue (5) | | 2025 | $23,646,004 | — | $27,664,592 | — | $5,871,297 | $6,296,156 | $71.87 | $119.92 | $1,293 | $9,775M | | 2024 | $24,166,665 | — | $1,250,864 | — | $6,365,146 | ($228,942) | $62.45 | $90.58 | $1,632 | $9,032M | | 2023 | $4,069,913 | — | ($4,498,193) | — | $6,258,401 | $4,222,331 | $105.68 | $91.84 | $1,161 | $9,675M | | 2022 | $30,488,593 | $26,625,221 | $27,551,849 | $5,898,711 | $5,878,461 | $4,969,529 | $113.09 | $88.53 | $3,047 | $10,326M | | 2021 | — | $17,689,665 | — | $15,211,025 | $5,761,560 | $5,081,944 | $97.98 | $99.37 | $1,556 | $11,054M |

  178. Narrative to Pay versus Performance Table

    Notes to Pay Versus Performance Table

  179. Narrative to Pay versus Performance Table

    | (1) The dollar amounts reported are the amounts of total compensation reported for our CEO, Mr. Viehbacher, and our former CEO, Mr. Vounatsos in the Summary Compensation Table for fiscal years 2025, 2024, 2023, 2022 and 2021. Mr. Vounatsos served as CEO for the full fiscal year 2021, while Mr. Viehbacher and Mr. Vounatsos both served as CEO in fiscal year 2022. |

  180. Narrative to Pay versus Performance Table

    | (2) The dollar amounts reported represent the amount of “compensation actually paid”, as computed in accordance with SEC rules. The dollar amounts do not reflect the actual amounts of compensation paid to our CEO and other NEOs during the applicable year, but also include (i) the year-end fair value of equity awards granted during the reported year and (ii) the change in fair value of equity awards that were unvested at the end of the prior year, measured through the date the awards vested or were forfeited, or through the end of the reported fiscal year. |

  181. Narrative to Pay versus Performance Table

    | 2026 Proxy Statement | - 62 - |

  182. Narrative to Pay versus Performance Table

    | (3) For 2025, reflects compensation information for our NEOs, other than our CEO, as described in the CD&A of this Proxy Statement. For 2024, reflects compensation information for Mr. McDonnell, Ms. Alexander, Dr. Singhal and Ms. Murphy. For 2023, reflects compensation information for Mr. McDonnell, Ms. Alexander, Ms. Murphy and Mr. Izzar. For 2022, reflects compensation information for Mr. McDonnell, Ms. Alexander, Dr. Gregory, Ms. Murphy and Mr. Guindo, our former EVP of Global Product Strategy and Commercialization. For 2021, reflects compensation information for Mr. McDonnell, Ms. Alexander, Mr. Guindo and Dr. Sandrock, our former EVP of R&D. |

  183. Narrative to Pay versus Performance Table

    | (4) Reflects cumulative total stockholder return of the NBI as of December 31, 2025. The NBI is the peer group used by Biogen for the purposes of Item 201(e) of Regulation S-K under the Exchange Act in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025. |

  184. Narrative to Pay versus Performance Table

    | (5) Revenue was adjusted to neutralize the effects of foreign exchange rate fluctuations. |

  185. Narrative to Pay versus Performance Table

    The following tables set forth the adjustments made during each year in the PVP table to arrive at “compensation actually paid” to our Principal Executive Officer during each year.

  186. Narrative to Pay versus Performance Table

    | Fiscal Year | Summary Compensation Table Total for CEO | Summary Compensation Table Total for former CEO | Reported Value of Equity Awards for CEO (1) | Reported Value of Equity Awards for former CEO (1) | Equity Award Adjustments for CEO (2) | Equity Award Adjustments for former CEO (2) | Compensation Actually Paid to CEO | Compensation Actually Paid to former CEO | | 2025 | $23,646,004 | — | $18,368,875 | — | $22,387,463 | — | $27,664,592 | — | | 2024 | $24,166,665 | — | $18,010,911 | — | ($4,904,890) | — | $1,250,864 | — | | 2023 | $4,069,913 | — | — | — | ($8,568,106) | — | ($4,498,193) | — | | 2022 | $30,488,593 | $26,625,221 | $30,000,655 | $15,389,732 | $27,063,911 | ($5,336,778) | $27,551,849 | $5,898,711 | | 2021 | — | $17,689,665 | — | $14,084,314 | — | $11,605,674 | — | $15,211,025 |

  187. Narrative to Pay versus Performance Table

    | (1) Represents the grant date fair value of equity awards to our CEO and former CEO, as reported in the “Stock Awards” and “Option Awards” columns in the Summary Compensation Table for each applicable year. |

  188. Narrative to Pay versus Performance Table

    | (2) Represents the year-over-year change in the fair value of equity awards to our CEO and former CEO, as itemized in the table below. No awards vested in the year they were granted. |

  189. Narrative to Pay versus Performance Table

    | Fair Value of Equity Awards for CEO and former CEO | 2025 | 2024 | 2023 | 2022 | | 2021 | | | | | | Mr. Viehbacher | Mr. Vounatsos | | | As of year-end for awards granted during the year | $22,312,724 | $8,702,498 | — | $27,063,911 | $1,996,870 | $10,985,776 | | Year-over-year increase or decrease of unvested awards granted in prior years | $266,557 | ($12,329,483) | ($7,204,687) | — | ($6,247,880) | ($687,744) | | Increase or decrease from prior fiscal year-end for awards that vested during the year | ($191,819) | ($1,277,904) | ($1,363,419) | — | ($1,085,768) | $1,307,643 | | Total Equity Award Adjustments | $22,387,463 | ($4,904,890) | ($8,568,106) | $27,063,911 | ($5,336,778) | $11,605,674 |

  190. Narrative to Pay versus Performance Table

    The following tables set forth the adjustments made during each year in the PVP table to arrive at “compensation actually paid” to our non-CEO NEOs during each year.

  191. Narrative to Pay versus Performance Table

    | Fiscal Year | Average Summary Compensation Table Total for Non-CEO NEOs | Average Reported Value of Equity Awards for Non-CEO NEOs (1) | Average Equity Award Adjustments for Non-CEO NEOs (2) | Average Compensation Actually Paid to Non-CEO NEOs | | 2025 | $5,871,297 | $4,230,214 | $4,655,074 | $6,296,156 | | 2024 | $6,365,146 | $4,156,541 | ($2,437,548) | ($228,942) | | 2023 | $6,258,401 | $4,503,143 | $2,467,073 | $4,222,331 | | 2022 | $5,878,461 | $4,223,226 | $3,314,294 | $4,969,529 | | 2021 | $5,761,560 | $4,105,942 | $3,426,326 | $5,081,944 |

  192. Narrative to Pay versus Performance Table

    | (1) Represents the average of the grant date fair value of the equity awards to our NEOs (other than our CEO and former CEO), as reported in the “Stock Awards” column in the Summary Compensation Tables for each applicable year. |

  193. Narrative to Pay versus Performance Table

    | (2) Represents the average of the year-over-year change in fair value of equity awards to our NEOs (other than our CEO and former CEO), as itemized in the table below. No awards vested in the year they were granted. |

  194. Narrative to Pay versus Performance Table

    | 2026 Proxy Statement | -6 3 - |

  195. Narrative to Pay versus Performance Table

    | Average Fair Value of Equity Awards for non-CEO NEOs | 2025 | 2024 | 2023 | 2022 | 2021 | | As of year-end for awards granted during the year | $5,138,456 | $2,008,250 | $3,523,016 | $3,809,706 | $3,295,987 | | Year-over-year increase or decrease of unvested awards granted in prior years | ($414,095) | ($4,156,500) | ($1,027,351) | ($241,427) | ($150,316) | | Increase or decrease from prior fiscal year-end for awards that vested during the year | ($69,287) | ($289,298) | ($28,591) | ($253,985) | $280,656 | | Total Equity Award Adjustments | $4,655,074 | ($2,437,548) | $2,467,073 | $3,314,294 | $3,426,326 |

  196. Narrative to Pay versus Performance Table

    The following table identifies the four most important financial and strategic measures used by our CMDC to link the CAP to our NEOs in 2025, as calculated in accordance with Item 402(v) of Regulation S-K, to company performance. The role each of these performance measures had on our NEOs’ compensation is discussed in the CD&A above.

  197. Narrative to Pay versus Performance Table

    | Most Important Performance Measures | | Growth Product Revenue | | Total Revenue | | Total Stockholder Return | | Non-GAAP Earnings Per Share | | Achievement of Pipeline Milestones |

  198. Narrative to Pay versus Performance Table

    | 2026 Proxy Statement | -6 4 - |

  199. Narrative to Pay versus Performance Table

    Biogen Inc.