UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 ORor 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): ~~October~~January 3013, ~~2025~~ 2026

~~BIOGEN~~Biogen ~~INC~~Inc.

(Exact name of registrant as specified in its charter)


Delaware	0-19311	33-0112644
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

225 Binney Street, Cambridge, Massachusetts 02142

(Address of principal executive offices; Zip Code)

Registrant’s telephone number, including area code: (617) 679-2000

Not Applicable

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common Stock, $0.0005 par value

BIIB

The Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

☐ Emerging growth company

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 Results of Operations and Financial Condition.

~~On October 30, 2025,~~ Biogen Inc. ~~issued~~(Biogen) aexpects ~~press~~that ~~release announcing~~ its ~~results~~GAAP ~~of operations~~ and ~~financial~~non-GAAP ~~condition~~results for the ~~third~~fourth quarter ~~ended~~of ~~September~~2025 30will include acquired in-process research and development, ~~2025.~~upfront Aand ~~copy~~milestone expense of ~~the~~approximately ~~press~~$222 million ~~release~~on a pre-tax basis. The estimated charge is ~~furnished~~expected asto ~~Exhibit~~impact ~~99.1~~GAAP and isnon-GAAP ~~incorporated~~net ~~herein~~income per diluted share for the fourth quarter 2025 by ~~reference~~approximately $1.26 per share.

~~The~~During ~~press~~the ~~release~~first isquarter ~~being~~of ~~furnished~~2025 ~~pursuant~~we tobegan ~~Item~~presenting ~~2.02~~acquired ofin-process ~~this~~research ~~Current~~and ~~Report~~development, onupfront ~~Form~~and 8milestone expense as a separate line item in our condensed consolidated statements of income. Acquired in-Kprocess research and ~~shall~~development, ~~not~~upfront beand ~~deemed~~milestone ~~“filed”~~expense ~~for~~includes ~~purposes~~costs ofincurred ~~Section~~in 18connection ofwith ~~the~~collaboration ~~Securities~~and ~~Exchange~~license ~~Act~~agreements ofsuch ~~1934~~as ~~(the~~upfront ~~“Exchange~~and ~~Act”)~~milestone orpayments ~~otherwise~~and, ~~subject~~when toapplicable, ~~the~~premiums ~~liabilities~~on equity securities and asset acquisitions of ~~that~~acquired ~~Section,~~in-process ~~nor~~research ~~shall~~and ~~such~~development. ~~document~~Biogen bedoes ~~deemed~~not ~~incorporated~~forecast bysuch ~~reference~~acquired in-process ~~any~~research ~~filing~~and ~~under~~development, upfront and milestone expense due to the ~~Securities~~uncertainty ~~Act~~of the future occurrence, magnitude and timing of ~~1933~~these ortransactions ~~the~~in ~~Exchange~~any ~~Act~~given period.

~~Item~~Results ~~9.01 Financial~~for ~~Statements~~the quarter ended December 31, 2025, have not been finalized and ~~Exhibits~~are subject to our financial statement closing procedures. There can be no assurance that our final results will not differ from the preliminary unaudited estimates described herein.

~~(d) Exhibits~~Note Regarding Forward-Looking Statements

~~The~~This ~~exhibits~~Current ~~listed~~Report ~~below~~on Form 8-K contains forward-looking statements relating to our financial and operating results and financial guidance, that are ~~furnished~~being asmade ~~part~~pursuant to the provisions of ~~this~~the ~~Current~~Private ~~Report~~Securities onLitigation ~~Form~~Reform 8Act of 1995 (the PSLRA) with the intention of obtaining the benefits of the “Safe Harbor” provisions of the PSLRA. These forward-Klooking statements may be accompanied by such words as “aim,” “anticipate,” "assume," “believe,” “contemplate,” “continue," "could," “estimate,” “expect,” “forecast,” “goal,” “guidance,” “hope,” “intend,” “may,” “objective,” "outlook," “plan,” “possible,” "potential," “predict,” “project,” “should,” “target,” “will,” “would” or the negative of these words or other words and terms of similar meaning.

Exhibit No.			Description
99.1			Biogen's press release dated October 30, 2025
104			Cover Page Interactive Data File (embedded within the Inline XBRL document)

Given their forward-looking nature, these statements involve substantial risks and uncertainties and may be based on inaccurate assumptions and could cause actual results to differ materially from those reflected in such statements. The information above includes, among others, forward-looking statements reflecting management’s current intentions and expectations for the future with respect to Biogen’s estimated acquired in-process research and development, upfront and milestone expense for the quarter ended December 31, 2025, and the related impact to Biogen’s GAAP and non-GAAP earnings per share for such period. These forward-looking statements are based on management's current beliefs and assumptions and on information currently available to management. Given their nature, we cannot assure that any outcome expressed in these forward-looking statements will be realized in whole or in part.

~~SIGNATURES~~These statements speak only as of the date of this Current Report on Form 8-K and are based on information and estimates available to us at this time. Should known or unknown risks or uncertainties materialize or should underlying assumptions prove inaccurate, actual results could vary materially from past results and those anticipated, estimated or projected. Investors are cautioned not to put undue reliance on forward-looking statements. A further list and description of risks, uncertainties and other matters can be found in our Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and in our subsequent reports on Form 10-Q and Form 10-K, in each case including in the sections thereof captioned “Note Regarding Forward-Looking Statements” and “Item 1A. Risk Factors,” and in our subsequent reports on Form 8-K. Except as required by law, we do not undertake any obligation to publicly update any forward-looking statements whether as a result of any new information, future events, changed circumstances or otherwise.

Signatures

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

~~BIOGEN~~Biogen ~~INC~~Inc. ~~By: /s/ Wendell Taylor Wendell Taylor Secretary~~

~~Date~~By: ~~October 30,~~/s/ ~~2025~~Wendell Taylor

Wendell Taylor

Secretary

Date: January 13, 2026

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