Biogen Inc.
    SEC Filings

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    All SEC filings by Biogen Inc. (BIIB) — annual and quarterly reports, current reports, registrations, proxies and ownership forms, updated in real time.

    Financials

    10-QQuarterly reportView DiffJul 29, 2026
    10-QQuarterly reportView DiffApr 29, 2026
    ARSAnnual report to shareholdersApr 28, 2026
    10-KAnnual reportView DiffFeb 6, 2026
    10-QQuarterly reportView DiffOct 30, 2025
    10-QQuarterly reportView DiffJul 31, 2025
    10-QQuarterly reportView DiffMay 1, 2025
    ARSAnnual report to shareholdersApr 25, 2025
    10-KAnnual reportView DiffFeb 12, 2025
    10-QQuarterly reportView DiffOct 30, 2024

    Events

    8-KBiogen Reports Strong Second Quarter 2026 Results Demonstrating Progress Toward Its Goal of Sustainable Revenue GrowthJul 29, 2026
    8-KCurrent reportJul 1, 2026
    8-KCurrent reportJun 10, 2026
    8-K/ACurrent reportJun 10, 2026
    8-KBiogen Completes Acquisition of Apellis PharmaceuticalsMay 14, 2026
    8-KBiogen Reports Strong First Quarter 2026 ResultsApr 29, 2026
    8-KResults of Operations and Financial ConditionApr 6, 2026
    8-KTender and Support AgreementMar 31, 2026
    8-KDeparture of Directors or Certain OfficersMar 11, 2026
    8-KDeparture of Directors or Certain OfficersFeb 11, 2026

    Registrations and Prospectuses

    SC TO-T/AThird party tender offer statementMay 14, 2026
    SC TO-T/AThird party tender offer statementMay 12, 2026
    SC TO-T/AThird party tender offer statementMay 6, 2026
    SC TO-TThird party tender offer statementApr 14, 2026
    SC TO-CInformation about tender offerApr 7, 2026
    SC TO-CInformation about tender offerApr 3, 2026
    SC TO-CInformation about tender offerMar 31, 2026
    SC TO-CInformation about tender offerMar 31, 2026
    424B2Prospectus for primary offeringMay 8, 2025
    FWPFree writing prospectusMay 6, 2025

    Proxies

    DEFA14AAdditional proxy soliciting materialsApr 28, 2026
    DEF 14ADefinitive proxyView DiffApr 28, 2026
    DEFA14AAdditional proxy soliciting materialsJun 2, 2025
    DEFA14AAdditional proxy soliciting materialsApr 25, 2025
    DEF 14ADefinitive proxyView DiffApr 25, 2025
    DEFA14AAdditional proxy soliciting materialsApr 26, 2024
    DEF 14ADefinitive proxyView DiffApr 26, 2024
    PRE 14APreliminary proxyApr 12, 2024
    DEFA14AAdditional proxy soliciting materialsJul 31, 2023
    DEFA14AAdditional proxy soliciting materialsJul 28, 2023

    Other

    EFFECTNotice of effectivenessJul 13, 2022
    EFFECTNotice of effectivenessMay 27, 2022
    CORRESPCorrespondence with SECMay 24, 2022
    UPLOADLetter from SECMay 23, 2022
    UPLOADLetter from SECJun 22, 2021
    CORRESPCorrespondence with SECJun 21, 2021
    UPLOADLetter from SECJun 17, 2021
    CORRESPCorrespondence with SECJun 9, 2021
    UPLOADLetter from SECMay 13, 2021
    CORRESPCorrespondence with SECApr 7, 2021

    Ownership

    4Parini MichaelSep 3, 2026
    3Parini MichaelAug 12, 2026
    SC 13G/ABeneficial ownership reportAug 6, 2026
    4Minor LloydAug 5, 2026
    144Notice of proposed sale of securitiesAug 4, 2026
    144Notice of proposed sale of securitiesAug 3, 2026
    4Hawkins William AJun 11, 2026
    4Sherwin Stephen AJun 11, 2026
    4Rowinsky Eric KJun 11, 2026
    4Mantas Jesus BJun 11, 2026