TEXT-EXTRACT 2 filename2.txt United States securities and exchange commission logo May 13, 2021 Michael McDonnell Executive Vice President and Chief Financial Officer BIOGEN INC. 225 Binney Street Cambridge, MA 02142 Re: BIOGEN INC. Form 10-K for Fiscal Year Ended December 31, 2020 Filed February 3, 2021 Form 8-K Filed February 3, 2021 Response dated April 7, 2021 File No. 000-19311 Dear Mr. McDonnell: We have reviewed your April 7, 2021 response to our comment letter and have the following comment. Please respond to this comment within ten business days by providing the requested information or advise us as soon as possible when you will respond. If you do not believe our comment applies to your facts and circumstances, please tell us why in your response. After reviewing your response to this comment, we may have additional comments. Form 8-K Filed February 3, 2021 Exhibit 99.1 1. We appreciate the information provided to us in your response letter and during the conference calls. We believe that your adjustments to exclude the upfront and premium payments made for collaboration agreements from R&D expense and net income attributable to Biogen, Inc. are inconsistent with the guidance in Question 100.01 of the Non-GAAP Financial Measures Compliance and Disclosure Interpretations. Please confirm to us that you will no longer include these adjustments in any non-GAAP financial measure presented in accordance with Item 10(e) of Regulation S-K or Regulation G. Michael McDonnell BIOGEN INC. May 13, 2021 Page 2 You may contact Tracey Houser at 202-551-3736, or Jeanne Baker at 202-551-3691, if you have questions regarding comments on the financial statements and related matters. FirstName LastNameMichael McDonnell Sincerely, Comapany NameBIOGEN INC. Division of Corporation Finance May 13, 2021 Page 2 Office of Life Sciences FirstName LastName