EX-21 6 biib-20231231xex21.htm EX-21

Exhibit 21

BIOGEN INC.

The following is a list of subsidiaries of Biogen Inc. as of December 31, 2023, omitting some subsidiaries which, considered in the aggregate, would not constitute a significant subsidiary.

SUBSIDIARY						STATE OR OTHER JURISDICTION OF INCORPORATION OR ORGANIZATION
Biogen Foundation Inc.						Massachusetts
Biogen MA Inc.						Massachusetts
Biogen Realty Corporation						Massachusetts
Biogen Realty Limited Partnership						Massachusetts
Biogen U.S. Corporation						Massachusetts
Biogen U.S. Limited Partnership						Massachusetts
Biogen (RTP) Realty LLC						Delaware
Biogen Chesapeake LLC						Delaware
Biogen Digital Health Inc.						Delaware
Biogen Digital Health Global LLC						Delaware
Biogen Holding I LLC						Delaware
Biogen Holding II LLC						Delaware
Biogen OUS Holding Inc.						Delaware
Biogen Manufacturing Holding LLC						Delaware
Biogen New Ventures Inc.						Delaware
Biogen SRO Inc.						Delaware
Biogen Therapeutics Inc.						Delaware
Biogen U.S. Pacific LLC						Delaware
Biogen U.S. West Corporation						Delaware
Conforma Therapeutics Corporation						Delaware
Stromedix, Inc.						Delaware
Nightstar, Inc.						Delaware
Reata Pharmaceuticals Global, Inc.						Delaware
Reata Pharmaceuticals Holdings, LLC.						Delaware
Reata Pharmaceuticals, Inc.						Delaware
Biogen (Argentina) SRL						Argentina
Biogen Australia PTY Ltd						Australia
Reata Australia PTY Ltd						Australia
Biogen Austria GmbH						Austria
Biogen Belgium N.V./S.A.						Belgium
Biogen International Holding Limited						Bermuda
Biogen (Bermuda) Technologies Ltd.						Bermuda
Biogen Brasil Produtos Farmaceuticos LTDA						Brazil
Biogen Canada Inc.						Canada
Biogen Chile SpA						Chile
Biogen Biotechnology (Shanghai) Co., Ltd						China
BIIB Colombia S.A.S.						Colombia
Biogen Pharma d.o.o.						Croatia
Biogen (Czech Republic) s.r.o.						Czech Republic
Biogen (Denmark) A/S						Denmark

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SUBSIDIARY						STATE OR OTHER JURISDICTION OF INCORPORATION OR ORGANIZATION
Biogen Estonia OU						Estonia
Biogen Finland OY						Finland
Biogen France S.A.S.						France
Reata France S.A.S.						France
Biogen GmbH						Germany
Reata Germany GmbH						Germany
Biogen Hong Kong Limited						Hong Kong
Biogen Hungary KFT						Hungary
Biogen Idec Biotech India Pvt. Ltd.						India
Biogen Capability Center India Private Limited						India
Biogen Idec (Ireland) Ltd.						Ireland
Nightstar Europa Limited						Ireland
Reata Ireland Limited						Ireland
Biogen Italia S.R.L.						Italy
Reata Italy S.R.L.						Italy
Biogen Japan Ltd.						Japan
Biogen Korea LLC						Korea
Biogen Latvia SIA						Latvia
Biogen Lithuania UAB						Lithuania
Biogen Luxembourg Holding S.a.r.l.						Luxembourg
Biogen Mexico S. de R.L. de C.V.						Mexico
Biogen NZ Biopharma Ltd.						New Zealand
Biogen Norway AS						Norway
Biogen Poland Sp. z.o.o.						Poland
Biogen Portugal Sociedade Farmaceutica, Unipessoal Lda.						Portugal
Biogen Regional Headquarters LLC						Saudi Arabia
Biogen Slovakia s.r.o.						Slovak Republic
Biogen Pharma, farmacevtska in biotehnoloska druzba, d.o.o.						Slovenia
Biogen Spain, S.L.						Spain
Biogen Sweden AB						Sweden
Biogen Digital Health International GmbH						Switzerland
Biogen International GmbH						Switzerland
Biogen International Neuroscience GmbH						Switzerland
Biogen Management Services GmbH						Switzerland
Biogen Swiss Manufacturing GmbH						Switzerland
Biogen Switzerland AG						Switzerland
Eidetica Biopharma GmbH						Switzerland
Reata Swiss International GmbH						Switzerland
Biogen Taiwan Limited						Taiwan
Biogen Turkey Ilac Ticaret Limited Sirketi						Turkey
Biogen B.V.						The Netherlands
Biogen Netherlands B.V.						The Netherlands
Biogen Idec Limited						United Kingdom
Biogen Idec Research Ltd.						United Kingdom
Convergence Pharmaceuticals Limited						United Kingdom
Convergence Pharmaceuticals Holdings Ltd.						United Kingdom
Old Convergence Pharmaceuticals Limited						United Kingdom
Reata U.K. Limited						United Kingdom

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SUBSIDIARY						STATE OR OTHER JURISDICTION OF INCORPORATION OR ORGANIZATION
Silver Acquisition Co. Ltd.						United Kingdom
Nightstar Therapeutics Limited						United Kingdom
NightstaRx Limited						United Kingdom
Tungsten Bidco Limited						United Kingdom
Biogen Idec Uruguay SA						Uruguay