FULLTEXT DEL 1 AV 2
10-Q – 2026-04-29 – biib-20260331.htm
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For the quarterly period ended March 31, 2026 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 33-0112644 (State or other jurisdiction of incorporation or organization) (I.R.S. Employer Identification No.) 225 Binney Street , Cambridge , MA 02142 ( 617 ) 679-2000 (Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices) 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 (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days: Yes x No o Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files): Yes x No o Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and "emerging growth company" in Rule 12b-2 of the Exchange Act: Large accelerated filer x Accelerated filer ☐ Non-accelerated filer ☐ Smaller reporting company ☐ 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. o Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No x The number of shares of the issuer’s Common Stock, $0.0005 par value, outstanding as of April 27, 2026, was 147,637,117 shares. Table of Contents BIOGEN INC. FORM 10-Q — Quarterly Report For the Quarterly Period Ended March 31, 2026 TABLE OF CONTENTS Page PART I — FINANCIAL INFORMATION Item 1. Financial Statements (unaudited) Condensed Consolidated Statements of Income — For the Three Months Ended March 31, 2026 and 2025 8 Condensed Consolidated Statements of Comprehensive Income — For the Three Months Ended March 31, 2026 and 2025 9 Condensed Consolidated Balance Sheets — As of March 31, 2026 and December 31, 2025 10 Condensed Consolidated Statements of Cash Flow — For the Three Months Ended March 31, 2026 and 2025 11 Condensed Consolidated Statements of Equity — For the Three Months Ended March 31, 2026 and 2025 12 Notes to Condensed Consolidated Financial Statements 13 Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations 43 Item 3. Quantitative and Qualitative Disclosures About Market Risk 67 Item 4. Controls and Procedures 69 PART II — OTHER INFORMATION Item 1. Legal Proceedings 70 Item 1A. Risk Factors 70 Item 2. Unregistered Sales of Equity Securities and Use of Proceeds 86 Item 5. Other Information 86 Item 6. Exhibits 87 Signatures 88 2 Table of Contents NOTE REGARDING FORWARD-LOOKING STATEMENTS This report contains forward-looking statements that are being made pursuant to the provisions of the Private Securities Litigation Reform Act of 1995 (the PSLRA) with the intention of obtaining the benefits of the “Safe Harbor” provisions of the PSLRA. These forward-looking 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,” "seek," “should,” “target,” “will,” “would” or the negative of these words or other words and terms of similar meaning. Given their forward-looking nature, these statements involve substantial risks and uncertainties and may be based on inaccurate assumptions. This report includes, among others, forward-looking statements regarding: • our expected financial and operating performance; • our long-term strategy and supporting business plans, including our product pipeline; • our expectations about continued growth through acquisitions and key collaborative relationships and funding arrangements; • our belief that our long-term competitive position depends upon our success in discovering and developing innovative, cost-effective products that serve unmet medical needs, along with our ability to manufacture products efficiently and to launch and market them effectively in a highly competitive environment; • our ability to obtain and maintain adequate coverage, pricing and reimbursement from third-party payors; • our expectations regarding certain legal and regulatory proceedings and investigations; and • our belief that our existing funds, when combined with cash generated from operations and our access to additional financing resources, if needed, are sufficient to satisfy our operating, working capital, strategic alliance, milestone payment, capital expenditure and debt service requirements for the foreseeable future. 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. We caution that these statements are subject to risks and uncertainties, many of which are outside of our control and could cause future events or results to be materially different from those stated or implied in this document, including, among others, factors relating to: • our substantial dependence on the anticipated amount, timing and accounting of revenue from our products, including from the successful development of new products and approval of additional indications for our existing products, including but not limited to LEQEMBI and SKYCLARYS; • the anticipated amount, timing and accounting of contingent, milestone, royalty and other payments under licensing, collaboration, acquisition or divestiture agreements; tax positions and contingencies; collectability of receivables; pre-approval inventory; cost of sales; research and development costs; compensation and other selling, general and administrative expense; amortization of intangible assets; foreign currency exchange risk; estimated fair value of assets and liabilities; and impairment assessments, including for goodwill balances; • expectations, plans, prospects and the timing of actions relating to product approvals, approvals of additional indications for our existing products, sales, pricing, growth, reimbursement and launch of our marketed and pipeline products all of which is subject to governmental and regulatory oversight, and therefore subject to risks and uncertainties, including but not limited to those related to approvals, unfavorable or delayed reimbursements and coverage determinations, and changes in reimbursement policies or practices of payors and other third parties; • the potential impact of increased product competition in the biopharmaceutical and healthcare industry, as well as any other markets in which we compete, including increased competition from new originator therapies, generics, prodrugs and biosimilars of existing products and products approved under abbreviated regulatory pathways, including generic, prodrugs or biosimilar versions of our marketed products or competing products, including but not limited to, increased competition from TECFIDERA generic entrants in the U.S. and international markets and a biosimilar entrant of TYSABRI; • patent terms, patent term extensions, patent office actions and expected availability and periods of regulatory exclusivities, as well as our ability to adequately enforce existing patents; • our ability to effectively implement our corporate strategy which includes significant investment in product and pipeline candidates, including but not limited to felzartamab, litifilimab and nusinersen; 3 Table of Contents • the successful execution of our strategic and growth initiatives, including acquisitions, and our ability to realize the anticipated benefits from our acquisitions of Reata, HI-Bio, Alcyone and the potential acquisition of Apellis, including future performance of the SKYCLARYS, EMPAVELI and SYFOVRE products, further development of the felzartamab product, future development of drug delivery solutions and anticipated synergies; • the drivers for growing our business, including our plans and intention to commit resources relating to discovery, research and development programs and business development opportunities, including collaboration agreements, as well as the potential benefits and results of, and the anticipated completion of, certain business development transactions, reorganizations and cost-reduction measures; • the expectations, development plans and anticipated timelines, including costs and timing of potential clinical trials, regulatory filing approvals and/or discontinuation, of our products, drug candidates and pipeline programs, including collaborations with third parties including but not limited to Eisai and Supernus, as well as the potential therapeutic scope of the development and commercialization of our and our collaborators’ pipeline products; • the impacts of disruptions, turnover or changes in strategy, priorities or capabilities at our collaborators resulting from, for example, a change in control, and the related impacts on the commercialization or manufacturing of our shared products; • the timing, outcome and impact of administrative, regulatory, legal and other proceedings, including those related to our patents and other proprietary and intellectual property rights, tax audits, assessments and settlements, pricing matters, sales and promotional practices, product liability, investigations and other matters; • our ability to commercialize biosimilars, which is subject to risks such as our reliance on third parties, competitive challenges, regulatory compliance, adequate supply, intellectual property and regulatory challenges and failure to gain market and patient acceptance; • our ability to finance our present and future operations and business initiatives and obtain funding for such activities on favorable terms; • our ability to attract, retain and motivate qualified individuals for management and other employee positions in a highly competitive environment, including potential difficulty in retaining talent following acquisitions or following the discontinuation or underperformance of one or more marketed, pre-clinical or clinical programs; • adverse safety events involving our marketed or pipeline products, generic, prodrugs or biosimilar versions of our marketed products or any other products from the same class as one of our products; • the current and potential impacts of geopolitical tensions, acts of war and other large-scale crises, including impacts to our operations, sales and the possible disruptions or delay in our plans to conduct clinical trial activities in areas of geopolitical tension, including tensions between the U.S., China and other countries, regions affected by Russia's invasion of Ukraine and the military conflict in the Middle East; • the direct and indirect impact of global health outbreaks or adverse weather events on our business and operations, including sales, expense, reserves and allowances, the supply chain, manufacturing, research and development costs, clinical trials and employees; • our use of information technology systems and data and the potential impacts of any breakdowns, interruptions, invasions, corruptions, data breaches, destructions and/or other cybersecurity incidents of such systems or those of our business partners; • our incorporation of technologies using AI into some of our processes; • the potential impact of healthcare reform in the U.S., including the IRA (or other legislative or executive acts that may modify or replace the IRA, such as the OBBBA) and the impact of the IRA Medicare Part D redesign, and measures being taken worldwide designed to reduce healthcare costs and limit the overall level of government expenditures, including the impact of pricing actions and reduced reimbursement for our products, as well as the potential impact of legislative and regulatory changes and priorities, including actions related to the MFN drug pricing policy; • our manufacturing capacity, including our ability to effectively manufacture biosimilars, reliance on third-party contract manufacturing organizations, plans and timing relating to changes in our manufacturing capabilities, our ability to adequately address global bulk supply risks, our ability to fully utilize our manufacturing facilities, 4 Table of Contents including our Solothurn facility, activities in new or existing manufacturing facilities and the expected timeline for the gene therapy, clinical packaging and other manufacturing facility in RTP, North Carolina to be operational; • the impact of the continued uncertainty of the credit and economic conditions in certain countries and our ability to collect accounts receivable in such countries; • the impact of the increased volatility in the financial markets on our ability to obtain financing; • lease commitments, purchase obligations and the timing and satisfaction of other contractual obligations; • changes in our effective tax rate and obligations in various jurisdictions in which we are subject to taxation; and • the impact of new laws, regulatory actions, judicial decisions, accounting standards and tariffs or trade restrictions, including any newly imposed U.S. tariffs and any responsive non-U.S. tariffs applicable to our products or operations, as well as the potential global macroeconomic effect of tariffs or trade restrictions. These forward-looking statements involve risks and uncertainties, including those that are described in Part II, Item 1A. Risk Factors and Part I, Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations included in this report and elsewhere in this report, that could cause actual results to differ materially from those reflected in such statements. The factors identified above should not be construed as an exhaustive list of factors that could affect our future results and should be read in conjunction with the other cautionary statements that are included in our 2025 Form 10-K. Because some of these risks and uncertainties cannot be predicted or quantified and some are beyond our control, you should not rely on our forward-looking statements as predictions of future events and you should not place undue reliance on these statements. Moreover, we operate in a very competitive and rapidly changing environment, new risks and uncertainties may emerge from time to time and it is not possible for us to predict all risks nor identify all uncertainties. Forward-looking statements speak only as of the date of this report and are based on information and estimates available to us at this time. Except as required by law, we do not undertake any obligation to publicly update any forward-looking statements, whether as a result of new information, future developments or otherwise. You should read this report with the understanding that our actual future results, performance, events and circumstances might be materially different from what we expect. NOTE REGARDING COMPANY AND PRODUCT REFERENCES References in this report to: • “Biogen,” the “company,” “we,” “us” and “our” refer to Biogen Inc. and its consolidated subsidiaries; and • “RITUXAN” refers to both RITUXAN (the trade name for rituximab in the U.S., Canada and Japan) and MabThera (the trade name for rituximab outside the U.S., Canada and Japan). NOTE REGARDING TRADEMARKS ADUHELM®, AVONEX®, PLEGRIDY®, QALSODY®, RITUXAN®, RITUXAN HYCELA®, SKYCLARYS®, SPINRAZA®, TECFIDERA®, THECAFLEX DRX®, TYSABRI® and VUMERITY® are registered trademarks of Biogen. BENEPALI™, FLIXABI™, FUMADERM™, IMRALDI™ and OPUVIZ™ are trademarks of Biogen. ACTEMRA®, COLUMVI®, EMPAVELI®, ENBREL®, EYLEA®, FAMPYRA™, GAZYVA®, LEQEMBI®, HUMIRA®, LUCENTIS®, LUNSUMIO®, OCREVUS®, REMICADE®, SYFOVRE®, TOFIDENCE®, ZURZUVAE® and other trademarks referenced in this report are the property of their respective owners. NOTE REGARDING DISCLOSURES From time to time, we have used, or expect in the future to use, our investor relations website (investors.biogen.com), the Biogen LinkedIn account (linkedin.com/company/biogen/-) and the Biogen X account (https://x.com/biogen) as a means of disclosing information to the public in a broad, non-exclusionary manner, including for purposes of the SEC’s Regulation Fair Disclosure (Reg FD). Accordingly, investors should monitor our investor relations website and these social media channels in addition to our press releases, SEC filings, public conference calls and websites, as the information posted on them could be material to investors. 5 Table of Contents DEFINED TERMS 2025 Form 10-K Annual Report on Form 10-K for the year ended December 31, 2025 2020 Share Repurchase Program Board of Directors authorized program to repurchase up to $5.0 billion of our common stock 2023 Term Loan $1.5 billion term loan credit agreement 2025 Senior Notes Senior Unsecured Notes Issued in May 2025 AbbVie AbbVie Inc. AI Artificial Intelligence Alcyone Alcyone Therapeutics, Inc. Alloy Alloy Therapeutics, Inc. ALS Amyotrophic Lateral Sclerosis Alteogen Alteogen Inc. AMR Antibody-Mediated Rejection AOCI Accumulated Other Comprehensive Income (Loss) Apellis Apellis Pharmaceuticals, Inc. ASO Antisense Oligonucleotide ASU Accounting Standards Update BLA Biologics License Application C3G C3 Glomerulopathy CCPA California Consumer Privacy Act CLE Cutaneous Lupus Erythematosus CLL Chronic Lymphocytic Leukemia CMS Centers for Medicare & Medicaid Services CNS Central Nervous System CODM Chief Operating Decision Maker CROs Contract Research Organizations Denali Denali Therapeutics Inc. District Court U.S. District Court for the District of Massachusetts EC European Commission Eisai Eisai Co., Ltd. EMA European Medicines Agency E.U. European Union FA Friedreich Ataxia FASB Financial Accounting Standards Board FCPA Foreign Corrupt Practices Act FDA U.S. Food and Drug Administration Fit for Growth Cost saving program initiated in 2023 GA Geographic Atrophy Genentech Genentech, Inc. GloBE Global Anti-Base Erosion GMP Good Manufacturing Practices HHS U.S. Department of Health and Human Services HI-Bio Human Immunology Biosciences, Inc. Humana Humana Inc. IC-MPGN Immune Complex Membranoproliferative Glomerulonephritis IEEPA International Emergency Economic Powers Act IgAN Immunoglobulin A Nephropathy IND Investigational New Drug IPR&D In-process Research and Development 6 Table of Contents DEFINED TERMS (continued) IRA Inflation Reduction Act of 2022 IT Information Technology IV Intravenous LEQEMBI Collaboration Agreement Amended and Restated Collaboration Agreement entered into by Biogen MA Inc. and Eisai Co., Ltd. on October 22, 2017, as amended on March 13, 2022 LRRK2 Leucine-Rich Repeat Kinase 2 MorphoSys MorphoSys AG MFN Most-Favored-Nation MS Multiple Sclerosis NCTI Net CFC Tested Income, previously known as Global Intangible Low-Taxed Income or GILTI Neurimmune Neurimmune SubOne AG NMPA National Medical Products Administration OBBBA Public Law 119-21, commonly referred to as the One Big Beautiful Bill Act OECD Organization for Economic Co-operation and Development Organon Organon LLC PDUFA Prescription Drug User Fee Act PHS Act Public Health Service Act PMN Primary Membranous Nephropathy PNH Paroxysmal Nocturnal Hemoglobinuria PPACA Patient Protection and Affordable Care Act PPD Postpartum Depression PPMS Primary Progressive MS PRV Priority Review Voucher R&D Research and Development Reata Reata Pharmaceuticals, Inc. RMS Relapsing MS RNAi RNA interference RTP Research Triangle Park Sage Sage Therapeutics, Inc. Samsung Bioepis Samsung Bioepis Co., Ltd. SEC U.S. Securities and Exchange Commission SG&A Selling, General and Administrative SLE Systemic Lupus Erythematosus SMA Spinal Muscular Atrophy SOD1 Superoxide Dismutase 1 Supernus Supernus Pharmaceuticals, Inc. SWISSMEDIC Swiss Agency for Therapeutic Products TJ Bio TJ Biopharma (Hangzhou) Co., Ltd. U.K. United Kingdom U.S. United States U.S. GAAP Accounting Principles Generally Accepted in the U.S. VA Veterans Affairs VAT Value-added Tax 7 Table of Contents PART I FINANCIAL INFORMATION BIOGEN INC. AND SUBSIDIARIES CONDENSED CONSOLIDATED STATEMENTS OF INCOME (unaudited, in millions, except per share amounts) For the Three Months Ended March 31, 2026 2025 Revenue: Product revenue, net $ 1,752.3 $ 1,726.5 Revenue from anti-CD20 therapeutic programs 419.1 378.2 Alzheimer's collaboration revenue 59.5 33.0 Contract manufacturing, royalty and other revenue 246.9 293.3 Total revenue 2,477.8 2,431.0 Cost and expense: Cost of sales, excluding amortization and impairment of acquired intangible assets 661.0 629.3 Research and development 539.0 434.1 Acquired in-process research and development, upfront and milestone expense 34.0 200.7 Selling, general and administrative 607.3 572.5 Amortization and impairment of acquired intangible assets 136.5 111.8 Collaboration profit sharing/(loss reimbursement) 74.2 58.1 (Gain) loss on fair value remeasurement of contingent consideration 20.5 9.6 Restructuring charges 7.9 35.3 Other (income) expense, net 19.7 68.4 Total cost and expense 2,100.1 2,119.8 Income before income tax (benefit) expense 377.7 311.2 Income tax (benefit) expense 58.2 70.7 Net income attributable to Biogen Inc. $ 319.5 $ 240.5 Net income per share: Basic earnings per share attributable to Biogen Inc. $ 2.17 $ 1.65 Diluted earnings per share attributable to Biogen Inc. $ 2.15 $ 1.64 Weighted-average shares used in calculating: Basic earnings per share attributable to Biogen Inc. 147.2 146.1 Diluted earnings per share attributable to Biogen Inc. 148.4 146.6 See accompanying notes to these unaudited condensed consolidated financial statements. 8 Table of Contents BIOGEN INC. AND SUBSIDIARIES CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited, in millions) For the Three Months Ended March 31, 2026 2025 Net income attributable to Biogen Inc. $ 319.5 $ 240.5 Other comprehensive income (loss): Unrealized gains (losses) on securities available for sale, net of tax ( 1.8 ) — Unrealized gains (losses) on cash flow hedges, net of tax 52.6 ( 57.8 ) Unrealized gains (losses) on pension benefit obligation, net of tax ( 0.5 ) 0.4 Currency translation adjustments, net of tax ( 8.5 ) 19.1 Total other comprehensive income (loss), net of tax 41.8 ( 38.3 ) Comprehensive income (loss) attributable to Biogen Inc. $ 361.3 $ 202.2 See accompanying notes to these unaudited condensed consolidated financial statements. 9 Table of Contents BIOGEN INC. AND SUBSIDIARIES CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited, in millions, except per share amounts) As of March 31, 2026 As of December 31, 2025 ASSETS Current assets: Cash and cash equivalents $ 3,382.7 $ 3,008.5 Current portion of marketable securities 900.0 807.2 Accounts receivable, net of allowance for doubtful accounts of $ 3.0 and $ 3.0 , respectively 1,369.2 1,342.4 Due from anti-CD20 therapeutic programs 421.2 524.6 Inventory 1,949.0 2,168.1 Other current assets 1,168.3 1,123.3 Total current assets 9,190.4 8,974.1 Marketable securities 465.6 431.9 Property, plant and equipment, net 3,017.9 3,055.4 Operating lease assets 251.3 265.4 Intangible assets, net 9,053.5 9,178.5 Goodwill 6,488.7 6,491.1 Deferred tax asset 238.2 292.5 Investments and other assets 777.5 750.6 Total assets $ 29,483.1 $ 29,439.5 LIABILITIES AND EQUITY Current liabilities: Taxes payable $ 93.6 $ 114.8 Accounts payable 358.5 432.0 Accrued expense and other 2,546.8 2,802.6 Total current liabilities 2,998.9 3,349.4 Notes payable 6,288.5 6,286.8 Deferred tax liability 483.5 507.6 Long-term operating lease liabilities 273.4 290.4 Other long-term liabilities 787.1 748.5 Total liabilities 10,831.4 11,182.7 Commitments, contingencies and guarantees Equity: Biogen Inc. shareholders’ equity: Preferred stock, par value $ 0.001 per share — — Common stock, par value $ 0.0005 per share 0.1 0.1 Additional paid-in capital 896.7 863.1 Accumulated other comprehensive income (loss) ( 140.2 ) ( 182.0 ) Retained earnings 20,872.2 20,552.7 Treasury stock, at cost ( 2,977.1 ) ( 2,977.1 ) Total equity 18,651.7 18,256.8 Total liabilities and equity $ 29,483.1 $ 29,439.5 See accompanying notes to these unaudited condensed consolidated financial statements. 10 Table of Contents BIOGEN INC. AND SUBSIDIARIES CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW (unaudited, in millions) For the Three Months Ended March 31, 2026 2025 Cash flow from operating activities: Net income $ 319.5 $ 240.5 Adjustments to reconcile net income to net cash flow from operating activities: Depreciation and amortization 204.4 183.2 Excess and obsolescence charges related to inventory 4.8 7.3 Amortization of acquired inventory step-up 107.6 51.4 Share-based compensation 84.0 81.0 Contingent consideration 20.5 9.6 Deferred income taxes 23.6 ( 27.8 ) (Gain) loss on strategic investments ( 19.0 ) 40.9 Other 28.0 6.7 Changes in operating assets and liabilities, net of effects of business acquired: Accounts receivable ( 33.7 ) ( 181.0 ) Due from anti-CD20 therapeutic programs 103.4 70.4 Inventory 116.2 62.0 Accrued expense and other current liabilities ( 243.2 ) ( 300.5 ) Income tax assets and liabilities 18.4 69.1 Other changes in operating assets and liabilities, net ( 89.0 ) ( 53.5 ) Net cash flow provided by (used in) operating activities 645.5 259.3 Cash flow from investing activities: Purchases of property, plant and equipment ( 51.2 ) ( 37.1 ) Proceeds from sales and maturities of marketable securities 625.2 — Purchases of marketable securities ( 748.8 ) — Acquired in-process research and development ( 35.0 ) — Acquisitions of intangible assets — ( 10.0 ) Proceeds from sales of strategic investments 0.5 — Other ( 0.2 ) ( 0.2 ) Net cash flow provided by (used in) investing activities ( 209.5 ) ( 47.3 ) Cash flow from financing activities: Payments related to issuance of stock for share-based compensation arrangements, net ( 55.1 ) ( 24.3 ) Other 11.3 1.3 Net cash flow provided by (used in) financing activities ( 43.8 ) ( 23.0 ) Net increase (decrease) in cash and cash equivalents 392.2 189.0 Effect of exchange rate changes on cash and cash equivalents ( 18.0 ) 34.3 Cash and cash equivalents, beginning of the period 3,008.5 2,375.0 Cash and cash equivalents, end of the period $ 3,382.7 $ 2,598.3 See accompanying notes to these unaudited condensed consolidated financial statements. 11 Table of Contents BIOGEN INC. AND SUBSIDIARIES CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (unaudited, in millions) For the Three Months Ended March 31, 2026 Preferred stock Common stock Additional paid-in capital Accumulated other comprehensive income (loss) Retained earnings Treasury stock Total equity Shares Amount Shares Amount Shares Amount Balance, December 31, 2025 — $ — 170.5 $ 0.1 $ 863.1 $ ( 182.0 ) $ 20,552.7 ( 23.8 ) $ ( 2,977.1 ) $ 18,256.8 Net income — — — — — — 319.5 — — 319.5 Other comprehensive income (loss), net of tax — — — — — 41.8 — — — 41.8 Issuance of common stock under stock option and stock purchase plans — — 0.1 — 15.2 — — — — 15.2 Issuance of common stock under stock award plan — — 0.8 — ( 70.3 ) — — — — ( 70.3 ) Compensation related to share-based payments — — — — 88.1 — — — — 88.1 Other — — — — 0.6 — — — — 0.6 Balance, March 31, 2026 — $ — 171.4 $ 0.1 $ 896.7 $ ( 140.2 ) $ 20,872.2 ( 23.8 ) $ ( 2,977.1 ) $ 18,651.7 For the Three Months Ended March 31, 2025 Preferred stock Common stock Additional paid-in capital Accumulated other comprehensive income (loss) Retained earnings Treasury stock Total equity Shares Amount Shares Amount Shares Amount Balance, December 31, 2024 — $ — 169.5 $ 0.1 $ 569.4 $ ( 136.2 ) $ 19,259.8 ( 23.8 ) $ ( 2,977.1 ) $ 16,716.0 Net income — — — — — — 240.5 — — 240.5 Other comprehensive income (loss), net of tax — — — — — ( 38.3 ) — — — ( 38.3 ) Issuance of common stock under stock option and stock purchase plans — — 0.2 — 15.2 — — — — 15.2 Issuance of common stock under stock award plan — — 0.6 — ( 39.5 ) — — — — ( 39.5 ) Compensation related to share-based payments — — — — 84.1 — — — — 84.1 Other — — — — 0.7 — — — — 0.7 Balance, March 31, 2025 — $ — 170.3 $ 0.1 $ 629.9 $ ( 174.5 ) $ 19,500.3 ( 23.8 ) $ ( 2,977.1 ) $ 16,978.7 See accompanying notes to these unaudited condensed consolidated financial statements. 12 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited) Note 1: Summary of Significant Accounting Policies References in these notes to "Biogen," the "company," "we," "us" and "our" refer to Biogen Inc. and its consolidated subsidiaries. Business Overview Biogen is a global biopharmaceutical company focused on discovering, developing and delivering innovative therapies for people living with serious and complex diseases. We have a broad portfolio of medicines to treat MS, have introduced the first approved treatment for SMA, co-developed treatments to address a defining pathology of Alzheimer’s disease and launched the first approved treatment to target a genetic cause of ALS. We market the first and only drug approved in the U.S., the E.U. and certain international markets for the treatment of FA in adults and adolescents aged 16 years and older. We are focused on advancing our pipeline in neurology, specialized immunology and rare diseases. We support our drug discovery and development efforts through internal research and development programs, external collaborations and acquisitions. Our marketed products include VUMERITY, TYSABRI, TECFIDERA, AVONEX and PLEGRIDY for the treatment of MS; SPINRAZA for the treatment of SMA; SKYCLARYS for the treatment of FA; and QALSODY for the treatment of ALS. We also have collaborations with Eisai on the commercialization of LEQEMBI for the treatment of Alzheimer's disease and Supernus on the commercialization of ZURZUVAE for the treatment of PPD. We have certain business and financial rights with respect to RITUXAN for the treatment of non-Hodgkin's lymphoma, CLL and other conditions; RITUXAN HYCELA for the treatment of non-Hodgkin's lymphoma and CLL; GAZYVA for the treatment of CLL, follicular lymphoma and lupus nephritis; OCREVUS for the treatment of PPMS and RMS; LUNSUMIO for the treatment of relapsed or refractory follicular lymphoma; COLUMVI, a bispecific antibody for the treatment of non-Hodgkin's lymphoma; and have the option to add other potential anti-CD20 therapies, pursuant to our collaboration arrangements with Genentech, a wholly owned member of the Roche Group. We commercialize a portfolio of biosimilars of advanced biologics including: BENEPALI, an etanercept biosimilar referencing ENBREL; IMRALDI, an adalimumab biosimilar referencing HUMIRA; and FLIXABI, an infliximab biosimilar referencing REMICADE. For additional information on our collaboration arrangements, please read Note 18, Collaborative and Other Relationships, to these unaudited condensed consolidated financial statements (condensed consolidated financial statements). Basis of Presentation In the opinion of management, our condensed consolidated financial statements include all adjustments, consisting of normal recurring accruals, necessary for a fair statement of our financial statements for interim periods in accordance with U.S. GAAP. The information included in this quarterly report on Form 10-Q should be read in conjunction with our audited consolidated financial statements and the accompanying notes included in our 2025 Form 10-K. Our accounting policies are described in the Notes to Consolidated Financial Statements in our 2025 Form 10-K and updated, as necessary, in this report. The year-end condensed consolidated balance sheet data presented for comparative purposes was derived from our audited financial statements, but does not include all disclosures required by U.S. GAAP. The results of operations for the three months ended March 31, 2026, are not necessarily indicative of the operating results for the full year or for any other subsequent interim period. We operate as one operating segment, focused on discovering, developing and delivering innovative therapies for people living with serious and complex diseases. Consolidation Our condensed consolidated financial statements reflect our financial statements, those of our wholly owned subsidiaries and variable interest entities where we are the primary beneficiary. For consolidated entities where we own or are exposed to less than 100.0 % of the economics, we record net income (loss) attributable to noncontrolling interests, net of tax in our condensed consolidated statements of income equal to the percentage of the economic or ownership interest retained in such entities by the respective noncontrolling parties. Intercompany balances and transactions are eliminated in consolidation. 13 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) In determining whether we are the primary beneficiary of a variable interest entity, we apply a qualitative approach that determines whether we have both (1) the power to direct the economically significant activities of the entity and (2) the obligation to absorb losses of, or the right to receive benefits from, the entity that could potentially be significant to that entity. We continuously assess whether we are the primary beneficiary of a variable interest entity as changes to existing relationships or future transactions may result in us consolidating or deconsolidating one or more of our collaborators or partners. Use of Estimates The preparation of our condensed consolidated financial statements requires us to make estimates, judgments and assumptions that may affect the reported amounts of assets, liabilities, equity, revenue and expense and related disclosure of contingent assets and liabilities. On an ongoing basis we evaluate our estimates, judgments and assumptions. We base our estimates on historical experience and on various other assumptions that we believe are reasonable, the results of which form the basis for making judgments about the carrying values of assets, liabilities and equity and the amount of revenue and expense. Actual results may differ from these estimates. Significant Accounting Policies There have been no material changes to our significant accounting policies disclosed in Note 1, Summary of Significant Accounting Policies , to our audited consolidated financial statements included in our 2025 Form 10-K. New Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that we adopt as of the specified effective date. Unless otherwise discussed below, we do not believe that the adoption of recently issued standards have had, or may have, a material impact on our condensed consolidated financial statements or disclosures. Standard Description Effective Date Effects on the financial statements ASU No. 2024-03, Income Statement (Subtopic 220-40): Reporting Comprehensive Income - Expense Disaggregation Disclosures This standard requires disclosure in the notes to the financial statements, at each interim and annual reporting period, of specified information about certain costs and expense including purchases of inventory, employee compensation, depreciation and intangible asset amortization included in each relevant expense caption. This standard also requires a qualitative description of the amounts remaining in relevant expense captions that are not separately disaggregated, as well as disclosure of the total amount of selling expenses, and, in annual reporting periods, an entity’s definition of selling expenses. Annual reporting for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. We are currently evaluating the potential impact that this new standard will have on our consolidated financial statements and related disclosures, and expect to apply this standard prospectively upon adoption. ASU No. 2025-06, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software This standard modernizes the accounting for software costs, including updating guidance on the recognition and measurement of costs incurred in connection with development and implementation activities related to internal-use software. Annual reporting for fiscal periods beginning after December 15, 2027, and interim periods within those annual reporting periods. Early adoption is permitted. We are currently evaluating the potential impact that this new standard will have on our consolidated financial statements and related disclosures. Note 2: Acquisitions Proposed Acquisition of Apellis Pharmaceuticals, Inc. In March 2026 we entered into an agreement to acquire all of the issued and outstanding shares of Apellis Pharmaceuticals, Inc., a commercial-stage biopharmaceutical company focused on the discovery, development and commercialization of novel therapeutic compounds to treat diseases with high unmet needs. As a result of this proposed acquisition we would acquire two FDA-approved products from Apellis: SYFOVRE (pegcetacoplan injection) for the treatment of geographic atrophy, or GA, an immune-mediated retinal disease; and EMPAVELI (pegcetacoplan) for the treatment of paroxysmal nocturnal hemoglobinuria, or PNH, a rare blood disorder, and C3 glomerulopathy, or C3G, and primary immune complex membranoproliferative glomerulonephritis, or primary IC-MPGN, in rare immune- 14 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) mediated kidney diseases. The addition of Apellis is expected to enhance our short- and long-term revenue growth profile by adding two commercialized differentiated immunology and rare disease medicines to our growth portfolio. Under the terms of the proposed acquisition, we would pay Apellis shareholders $ 41.00 per share in cash, representing an expected total transaction value of approximately $ 5.6 billion, and one contractual, non-transferable contingent value right per share representing the right to receive contingent cash payments of up to an aggregate of $ 4.00 in cash, subject to the achievement of specified annual global net sales thresholds for SYFOVRE. We plan to fund the proposed acquisition of Apellis through approximately $ 3.6 billion of available cash and marketable securities on hand, supplemented by approximately $ 2.0 billion in bank loans. We expect this transaction to be accounted for as a business combination and to include the results of operations in our condensed consolidated financial statements from the acquisition date. Alcyone Therapeutics, Inc. In November 2025 we completed the acquisition of all of the issued and outstanding shares of Alcyone Therapeutics, Inc., a clinical-stage biotechnology company focused on pediatric care through precision CNS therapeutics and dosing platforms. The lead asset acquired is ThecaFlex DRx, an implantable subcutaneous port and catheter device being investigated for the intrathecal delivery of ASOs, including SPINRAZA, that is designed to provide an alternative to repeat lumbar punctures in chronic intrathecal administration of medicines. Total consideration for this transaction was approximately $ 85.0 million, comprising of a $ 50.0 million payment made upon closing and a $ 35.0 million payment that was considered probable as of December 31, 2025, and made upon FDA approval of a supplemental application in January 2026. This consideration was recorded within acquired in-process research and development, upfront and milestone expense within our consolidated statements of income for the year ended December 31, 2025, included in our 2025 Form 10-K. We may pay additional development and regulatory milestone payments to the former shareholders of Alcyone of up to a total of $ 75.0 million if approval is received for ThecaFlex DRx administration of SPINRAZA or other additional pipeline products. We accounted for this transaction as an asset acquisition as the value being acquired primarily relates to a single asset. U nder the terms of this acquisition, we will oversee the end-to-end development, manufacturing and commercialization of ThecaFlex DRx . Alcyone's remaining therapeutic assets were divested from Alcyone into Neela Therapeutics, Inc., a newly formed independent company, prior to the closing of this acquisition. Note 3: Dispositions Sale of TOFIDENCE In March 2025 we completed the sale of our regulatory and commercial rights in the U.S. for TOFIDENCE, a tocilizumab biosimilar referencing ACTEMRA, to Organon. Under the terms of this transaction, we received a payment of approximately $ 51.0 million in July 2025 a nd recognized a de minimis loss within our condensed consolidated statements of income for the three months ended March 31, 2025. Note 4: Restructuring 2023 Fit for Growth Restructuring Program In 2023 we initiated cost saving measures as part of our Fit for Growth program to reduce operating costs, while improving operating efficiency and effectiveness. The Fit for Growth program generated approximately $ 1.0 billion in gross operating expense savings by the end of 2025, some of which has been reinvested in various initiatives. The Fit for Growth program included net headcount reductions of approximately 1,400 employees and we incurred total restructuring charges of approximately $ 320.0 million by the end of 2025. For the three months ended March 31, 2025, we recorded approximately $ 35.3 million in restructuring charges related to severance costs from our Fit for Growth program within restructuring charges in our condensed consolidated statements of income. 15 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Restructuring Reserve Charges and spending related to workforce reductions are summarized as follows: Workforce Reductions (In millions) 2026 2025 Restructuring reserve as of January 1 $ 15.8 $ 31.9 Expense 7.9 35.3 Payment ( 10.3 ) ( 25.8 ) Foreign currency and other adjustments 0.2 ( 1.0 ) Restructuring reserve as of March 31 $ 13.6 $ 40.4 16 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Note 5: Revenue Product Revenue Revenue by product is summarized as follows: For the Three Months Ended March 31, 2026 2025 (In millions) United States Rest of World Total United States Rest of World Total Multiple Sclerosis: TECFIDERA $ 31.4 $ 78.1 $ 109.5 $ 39.8 $ 166.3 $ 206.1 VUMERITY 153.4 25.6 179.0 117.1 21.7 138.8 Total Fumarate 184.8 103.7 288.5 156.9 188.0 344.9 AVONEX 108.5 54.7 163.2 108.6 58.2 166.8 PLEGRIDY 24.3 40.0 64.3 24.1 35.4 59.5 Total Interferon 132.8 94.7 227.5 132.7 93.6 226.3 TYSABRI 241.8 199.7 441.5 200.8 180.7 381.5 FAMPYRA (1) — — — — 0.3 0.3 Subtotal: Multiple Sclerosis 559.4 398.1 957.5 490.4 462.6 953.0 Rare Disease: SPINRAZA 142.2 231.8 374.0 154.4 269.5 423.9 SKYCLARYS 71.8 78.9 150.7 69.1 54.8 123.9 QALSODY 10.5 22.0 32.5 7.5 8.0 15.5 Subtotal: Rare Disease 224.5 332.7 557.2 231.0 332.3 563.3 Biosimilars: BENEPALI — 122.1 122.1 — 111.3 111.3 IMRALDI — 49.6 49.6 — 47.4 47.4 FLIXABI — 10.5 10.5 — 13.1 13.1 BYOOVIZ (2) — — — 4.2 4.7 8.9 TOFIDENCE (2) — — — 0.1 — 0.1 Subtotal: Biosimilars — 182.2 182.2 4.3 176.5 180.8 Other: ZURZUVAE 55.3 0.1 55.4 27.7 — 27.7 Other (3) — — — 0.4 1.3 1.7 Subtotal: Other 55.3 0.1 55.4 28.1 1.3 29.4 Total product revenue, net $ 839.2 $ 913.1 $ 1,752.3 $ 753.8 $ 972.7 $ 1,726.5 (1) Effective January 1, 2025, our collaboration and license agreement for FAMPYRA global commercialization rights was terminated. (2) In 2025 we completed the sale of our rights to TOFIDENCE and BYOOVIZ. (3) Other includes FUMADERM and ADUHELM. We recognized revenue from two wholesalers accounting for 27.3 % and 14.7 % of gross product revenue for the three months ended March 31, 2026, compared to 25.9 % and 14.1 % of gross product revenue for the three months ended March 31, 2025. 17 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) An analysis of the change in reserves for discounts and allowances is summarized as follows: (In millions) Discounts Contractual Adjustments Returns Total Balance, December 31, 2025 $ 115.7 $ 1,046.1 $ 49.0 $ 1,210.8 Current provisions relating to sales in current year 214.0 683.7 7.3 905.0 Adjustments relating to prior years 0.8 ( 28.4 ) 10.4 ( 17.2 ) Payments/credits relating to sales in current year ( 133.4 ) ( 255.3 ) ( 0.1 ) ( 388.8 ) Payments/credits relating to sales in prior years ( 92.3 ) ( 426.0 ) ( 14.9 ) ( 533.2 ) Balance, March 31, 2026 $ 104.8 $ 1,020.1 $ 51.7 $ 1,176.6 The total reserves above, which are included in our condensed consolidated balance sheets, are summarized as follows: (In millions) As of March 31, 2026 As of December 31, 2025 Component of accrued expense and other $ 961.1 $ 1,000.4 Reduction of accounts receivable 215.5 210.4 Total revenue-related reserves $ 1,176.6 $ 1,210.8 Revenue from Anti-CD20 Therapeutic Programs Revenue from anti-CD20 therapeutic programs is summarized in the table below. For the purposes of this footnote, we refer to RITUXAN and RITUXAN HYCELA collectively as RITUXAN. For the Three Months Ended March 31, (In millions) 2026 2025 Royalty revenue on sales of OCREVUS $ 317.2 $ 288.8 Biogen’s share of pre-tax profits in the U.S. for RITUXAN, GAZYVA and LUNSUMIO 94.7 83.7 Other revenue from anti-CD20 therapeutic programs 7.2 5.7 Total revenue from anti-CD20 therapeutic programs $ 419.1 $ 378.2 For additional information on our collaboration arrangements with Genentech, please read Note 18, Collaborative and Other Relationships, to these condensed consolidated financial statements. Alzheimer's Collaboration Revenue Alzheimer's collaboration revenue consists of our 50.0 % share of LEQEMBI product revenue, net and cost of sales, including royalties, as we are not the principal. We began recognizing Alzheimer's collaboration revenue upon the accelerated approval of LEQEMBI in the U.S. during the first quarter of 2023. For the three months ended March 31, 2026 and 2025, we recognized Alzheimer's collaboration revenue of approximately $ 59.5 million and $ 33.0 million, respectively. For additional information on our collaboration arrangements with Eisai, please read Note 18, Collaborative and Other Relationships , to these condensed consolidated financial statements. Contract Manufacturing, Royalty and Other Revenue Contract manufacturing, royalty and other revenue is summarized as follows: For the Three Months Ended March 31, (In millions) 2026 2025 Contract manufacturing revenue $ 237.2 $ 282.3 Royalty and other revenue 9.7 11.0 Total contract manufacturing, royalty and other revenue $ 246.9 $ 293.3 18 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Contract Manufacturing Revenue Contract manufacturing revenue primarily reflects amounts earned under contract manufacturing agreements with our strategic customers and batches of LEQEMBI related to our collaboration with Eisai. Royalty and Other Revenue Royalty and other revenue primarily reflects royalty revenue on biosimilar products from our license arrangements with Samsung Bioepis and royalties we receive from net sales on products related to patents that we have out-licensed. For additional information on our license arrangements with Samsung Bioepis and our collaboration arrangements with Eisai, please read Note 18, Collaborative and Other Relationships , to these condensed consolidated financial statements. Note 6: Inventory The components of inventory are summarized as follows: (In millions) As of March 31, 2026 As of December 31, 2025 Raw materials $ 278.7 $ 293.4 Work in process 1,351.6 1,595.2 Finished goods 458.2 424.9 Total inventory $ 2,088.5 $ 2,313.5 Balance Sheet Classification: Inventory $ 1,949.0 $ 2,168.1 Investments and other assets 139.5 145.4 Total inventory $ 2,088.5 $ 2,313.5 Long-term inventory is included in investments and other assets within our condensed consolidated balance sheets. As a result of our acquisition of Reata in September 2023 we recorded a fair value step-up adjustment related to the acquired inventory of SKYCLARYS of approximately $ 1.3 billion. This fair value step-up adjustment is being amortized to cost of sales as the inventory is sold or research and development expense as the inventory is used for clinical purposes within our condensed consolidated statements of income. We expect this amount to be fully amortized by the end of 2028. For the three months ended March 31, 2026 and 2025, amortization from the fair value step-up adjustment was approximately $ 107.6 million and $ 51.4 million, respectively. For the three months ended March 31, 2026, amortization from the fair value step-up adjustment includes approximately $ 56.8 million of inventory used for clinical purposes, which is reflected in research and development expense within our condensed consolidated statements of income. For additional information on our acquisition of Reata, please read Note 2, Acquisitions , to our consolidated financial statements included in our 2025 Form 10-K. 19 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Note 7: Intangible Assets and Goodwill Intangible Assets Intangible assets, net of accumulated amortization, impairment charges and adjustments are summarized as follows: As of March 31, 2026 As of December 31, 2025 (In millions) Estimated Life Cost Accumulated Amortization Net Cost Accumulated Amortization Net Completed technology 1 - 30 years $ 14,078.8 $ ( 6,824.3 ) $ 7,254.5 $ 14,067.3 $ ( 6,687.8 ) $ 7,379.5 In-process research and development Indefinite until commercialization 1,635.0 — 1,635.0 1,635.0 — 1,635.0 Priority review voucher Indefinite 100.0 — 100.0 100.0 — 100.0 Trademarks and trade names Indefinite 64.0 — 64.0 64.0 — 64.0 Total intangible assets $ 15,877.8 $ ( 6,824.3 ) $ 9,053.5 $ 15,866.3 $ ( 6,687.8 ) $ 9,178.5 Amortization and Impairments For the three mont hs ended March 31, 2026, amortization and impairment of acquired intangible assets totaled $ 136.5 million, compared to $ 111.8 million in the prior year comparative period. The increase was primarily due to amortization for the acquired intangible assets associated with SKYCLARYS and TYSABRI. For the three months ended March 31, 2026 and 2025, we had no impairment charges. Completed Technology Completed technology primarily relates to our other marketed products and programs acquired through asset acquisitions, licenses and business combinations. Completed technology intangible assets are amortized over their estimated useful lives, which range between approximately 1 to 30 years, with a remaining weighted average useful life of 11 years as of March 31, 2026. IPR&D Related to Business Combinations IPR&D represents the fair value assigned to research and development assets that we acquired as part of a business combination and had not yet reached technological feasibility at the date of acquisition. The carrying value associated with our IPR&D assets as of March 31, 2026 and December 31, 2025, primarily relates to the IPR&D programs we acquired in connection with our acquisition of HI-Bio in July 2024, with an estimated fair value of approximately $ 1.6 billion. Priority Review Voucher In connection with our acquisition of Reata in September 2023 we acquired a rare pediatric disease PRV which may be used to obtain priority review by the FDA for a future regulatory submission or sold to a third party. We recorded the PRV based on its estimated fair value of $ 100.0 million as an intangible asset. Estimated Future Amortization of Intangible Assets The estimated future amortization of finite-lived intangible assets for the next five years is expected to be as follows: (In millions) As of March 31, 2026 2026 (remaining nine months) $ 400.0 2027 485.0 2028 525.0 2029 575.0 2030 650.0 2031 700.0 20 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Goodwill The following table provides a roll forward of the changes in our goodwill balance: (In millions) As of March 31, 2026 Goodwill, December 31, 2025 $ 6,491.1 Other (1) ( 2.4 ) Goodwill, March 31, 2026 $ 6,488.7 (1) Other includes adjustments related to foreign currency exchange rate fluctuations. As of March 31, 2026, we had no impairment losses related to goodwill. Note 8: Fair Value Measurements The tables below present information about our assets and liabilities that are regularly measured and carried at fair value and indicate the level within the fair value hierarchy of the valuation techniques we utilized to determine such fair value: Fair Value Measurements on a Recurring Basis As of March 31, 2026 (In millions) Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Cash equivalents $ 2,512.8 $ — $ 2,512.8 $ — Marketable debt securities: Corporate debt securities 734.2 — 734.2 — Government securities 547.3 547.3 — Mortgage and other asset backed securities 84.1 84.1 — Marketable equity securities 137.4 137.4 — — Other current assets: Derivative contracts 19.1 — 19.1 — Other non-current assets: Convertible note (1) 35.0 — — 35.0 Plan assets for deferred compensation 56.8 — 56.8 — Derivative contracts 5.9 — 5.9 — Total $ 4,132.6 $ 137.4 $ 3,960.2 $ 35.0 Liabilities: Other current liabilities: Derivative contracts $ 38.2 $ — $ 38.2 $ — Other non-current liabilities: Contingent consideration obligations 266.9 — — 266.9 Total $ 305.1 $ — $ 38.2 $ 266.9 (1) Convertible notes includes a $ 30.0 million convertible note we invested in as part of our strategic research arrangement with City Therapeutics during 2025, as well as a $ 5.0 million convertible note we invested into Neela Therapeutics, Inc. during 2025. We elected the fair value option for both convertible notes. For additional information on the arrangement with City Therapeutics, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in our 2025 Form 10-K. 21 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Fair Value Measurements on a Recurring Basis As of December 31, 2025 (In millions) Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Cash equivalents $ 2,233.2 $ — $ 2,233.2 $ — Marketable debt securities: Corporate debt securities 537.6 — 537.6 — Government securities 648.8 — 648.8 — Mortgage and other asset backed securities 52.7 — 52.7 — Marketable equity securities 118.1 118.1 — — Other current assets: Derivative contracts 10.0 — 10.0 — Other non-current assets: Convertible notes (1) 35.0 — — 35.0 Plan assets for deferred compensation 52.2 — 52.2 — Derivative contracts 0.4 — 0.4 — Total $ 3,688.0 $ 118.1 $ 3,534.9 $ 35.0 Liabilities: Other current liabilities: Derivative contracts $ 56.7 $ — $ 56.7 $ — Other non-current liabilities: Derivative contracts 2.2 — 2.2 — Contingent consideration obligations 246.4 — — 246.4 Total $ 305.3 $ — $ 58.9 $ 246.4 (1) Convertible notes includes a $ 30.0 million convertible note we invested in as part of our strategic research arrangement with City Therapeutics during 2025, as well as a $ 5.0 million convertible note we invested into Neela Therapeutics, Inc. during 2025. We elected the fair value option for both convertible notes. For additional information on the arrangement with City Therapeutics, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in our 2025 Form 10-K. Our marketable equity securities represent investments in publicly traded equity securities. Our ability to liquidate our investment in Denali may be limited by the size of our interest, the volume of market-related activity, our concentrated level of ownership and potential restrictions resulting from our status as a collaborator. Therefore, we may realize significantly less than the current value of such investments. For additional information on our investment in Denali common stock, please read Note 9, Financial Instruments , and Note 17, Other Consolidated Financial Statement Detail , to these condensed consolidated financial statements. There have been no material impairments of our assets measured and carried at fair value as of March 31, 2026 and December 31, 2025. In addition, there have been no changes to our valuation techniques as of March 31, 2026 and December 31, 2025. For a description of our validation procedures related to prices provided by third-party pricing services and our option pricing valuation model, please read Note 1, Summary of Significant Accounting Policies - Fair Value Measurements, to our consolidated financial statements included in our 2025 Form 10-K. Level 3 Assets and Liabilities Held at Fair Value The following tables present quantitative information, as of the dates indicated, about the valuation techniques and significant unobservable inputs used in the valuation of our Level 3 financial assets and liabilities measured at fair value on a recurring basis: 22 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Quantitative Information about Level 3 Fair Value Measurements As of March 31, 2026 (In millions) Fair Value Valuation Technique Significant Unobservable Input(s) Range Weighted Average Liabilities: Contingent consideration obligations $ 266.9 Discounted cash flow Discount rate 5.7 % 5.7 % Expected timing of achievement of development milestones 2028 — Quantitative Information about Level 3 Fair Value Measurements As of December 31, 2025 (In millions) Fair Value Valuation Technique Significant Unobservable Input(s) Range Weighted Average Liabilities: Contingent consideration obligations $ 246.4 Discounted cash flow Discount rate 5.3 % - 5.4 % 5.4 % Expected timing of achievement of development milestones 2028 - 2030 — The weighted average discount rates were calculated based on the relative fair values of each distinct contingent consideration obligation related to our acquisition of HI-Bio in July 2024. In addition, we apply various probabilities of technological and regulatory success to the valuation models to estimate the fair values of these contingent consideration obligations, which ranged from approximately 75.0 % to 95.0 % as of March 31, 2026. There were no transfers of assets or liabilities into or out of Level 3 as of March 31, 2026 and December 31, 2025. Contingent Consideration Obligations In connection with our acquisition of HI-Bio in July 2024 we agreed to make additional payments based upon the achievement of certain milestone events. The following table provides a roll forward of the fair value of our contingent consideration obligations, which were classified as Level 3 measurements: For the Three Months Ended March 31, (In millions) 2026 2025 Fair value, beginning of period $ 246.4 $ 512.8 Changes in fair value 20.5 9.6 Fair value, end of period $ 266.9 $ 522.4 Changes in the fair value of our contingent consideration obligations, other than changes due to payments, are recognized as a (gain) loss on fair value remeasurement of contingent consideration in our condensed consolidated statements of income. The fair values of the contingent consideration liabilities were based on a probability-adjusted discounted cash flow calculation using Level 3 fair value measurements and inputs. For additional information on the valuation techniques and inputs utilized in the valuation of our financial assets and liabilities, please read Note 1, Summary of Significant Accounting Policies , to our consolidated financial statements included in our 2025 Form 10-K. As of March 31, 2026 and December 31, 2025, approximately $ 266.9 million and $ 246.4 million, respectively, of the fair value of our contingent consideration obligations were classified as long-term and reflected as a component of other long-term liabilities in our condensed consolidated balance sheets. F or the three months ended March 31, 2026 , changes in the fair value of our contingent consideration obligations were primarily due to changes in the probabilities of success and expected timing of the achievement of certain remaining developmental milestones. During the second quarter of 2025 the first milestone related to the fourth patient dosed in a phase 3 clinical trial of felzartamab for AMR was achieved, resulting in a $ 150.0 million milestone payment made to the former shareholders of HI-Bio, which was paid during the third quarter of 2025. In October 2025 the second milestone related to the fourth patient dosed in a phase 3 clinical trial of felzartamab for IgAN was achieved, resulting in a $ 150.0 million milestone payment made to the former shareholders of HI-Bio during the fourth quarter of 2025. 23 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Financial Instruments Not Carried at Fair Value Other Financial Instruments Due to the short-term nature of certain financial instruments, the carrying value reflected in our condensed consolidated balance sheets for current accounts receivable, due from anti-CD20 therapeutic programs, other current assets, accounts payable and accrued expense and other, approximates fair value. Debt Instruments The fair and carrying values of our debt instruments, which are Level 2 liabilities, are summarized as follows: As of March 31, 2026 As of December 31, 2025 (In millions) Fair Value Carrying Value Fair Value Carrying Value Non-current portion: 2.250 % Senior Notes due May 1, 2030 $ 1,369.5 $ 1,495.9 $ 1,378.7 $ 1,495.7 5.050 % Senior Notes due January 15, 2031 407.5 398.1 413.0 398.0 5.750 % Senior Notes due May 15, 2035 672.5 645.6 684.5 645.5 5.200 % Senior Notes due September 15, 2045 1,004.8 1,101.6 1,029.5 1,101.5 3.150 % Senior Notes due May 1, 2050 943.9 1,475.8 973.0 1,475.6 3.250 % Senior Notes due February 15, 2051 443.6 481.3 461.8 480.3 6.450 % Senior Notes due May 15, 2055 725.9 690.2 737.6 690.2 Non-current portion of notes payable 5,567.7 6,288.5 5,678.1 6,286.8 Total notes payable $ 5,567.7 $ 6,288.5 $ 5,678.1 $ 6,286.8 The fair values of each of our series of Senior Notes were determined through market, observable and corroborated sources. The changes in the fair values of our Senior Notes as of March 31, 2026, compared to December 31, 2025, are primarily related to increases in U.S. treasury yields and credit spreads used to value our Senior Notes since December 31, 2025. For additional information related to our Senior Notes, please read Note 13, Indebtedness, to our consolidated financial statements included in our 2025 Form 10-K. Note 9: Financial Instruments The following table summarizes our financial assets with maturities of less than 90 days from the date of purchase included in cash and cash equivalents in our condensed consolidated balance sheets: (In millions) As of March 31, 2026 As of December 31, 2025 Money market funds $ 1,949.4 $ 2,027.7 Overnight reverse repurchase agreements 34.3 70.0 Short-term debt securities 391.8 15.4 Commercial paper 137.3 120.1 Total $ 2,512.8 $ 2,233.2 The carrying values of our money market funds, overnight reverse repurchase agreements, short-term debt securities and commercial paper, including accrued interest, approximate fair value due to their short-term maturities. 24 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Our marketable equity securities gains (losses) are recorded in other (income) expense, net in our condensed consolidated statements of income. The following tables summarize our marketable debt and equity securities, classified as available-for-sale: As of March 31, 2026 (In millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Marketable debt securities Corporate debt securities: Current $ 418.2 $ — $ ( 0.7 ) $ 417.5 Non-current 317.8 — ( 1.1 ) 316.7 Government securities: Current 482.6 — ( 0.1 ) 482.5 Non-current 64.8 — — 64.8 Mortgage and other asset backed securities: Non-current 84.2 — ( 0.1 ) 84.1 Total marketable debt securities $ 1,367.6 $ — $ ( 2.0 ) $ 1,365.6 Marketable equity securities Marketable equity securities, non-current $ 227.8 $ — $ ( 90.4 ) $ 137.4 Total marketable equity securities $ 227.8 $ — $ ( 90.4 ) $ 137.4 As of December 31, 2025 (In millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Marketable debt securities Corporate debt securities: Current $ 246.8 $ — $ — $ 246.8 Non-current 290.6 0.2 — 290.8 Government securities: Current 560.4 — — 560.4 Non-current 88.4 — — 88.4 Mortgage and other asset backed securities: Non-current 52.7 — — 52.7 Total marketable debt securities $ 1,238.9 $ 0.2 $ — $ 1,239.1 Marketable equity securities Marketable equity securities, non-current $ 227.7 $ — $ ( 109.6 ) $ 118.1 Total marketable equity securities $ 227.7 $ — $ ( 109.6 ) $ 118.1 25 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Summary of Contractual Maturities: Available-for-Sale Debt Securities The estimated fair value and amortized cost of our marketable debt securities classified as available-for-sale by contractual maturity are summarized as follows: As of March 31, 2026 As of December 31, 2025 (In millions) Estimated Fair Value Amortized Cost Estimated Fair Value Amortized Cost Due in one year or less $ 900.0 $ 900.8 $ 807.2 $ 807.2 Due after one year through five years 454.7 455.9 419.5 419.3 Due after five years 10.9 10.9 12.4 12.4 Total marketable debt securities $ 1,365.6 $ 1,367.6 $ 1,239.1 $ 1,238.9 The average maturity of our marketable debt securities classified as available-for-sale as of March 31, 2026, was approximately 10 months. Proceeds from Marketable Debt Securities The proceeds from maturities and sales of marketable debt securities and any resulting realized gains and losses are summarized as follows: For the Three Months Ended March 31, (In millions) 2026 2025 Proceeds from maturities and sales $ 625.2 $ — Strategic Investments Our strategic investment portfolio includes investments in equity securities of certain biotechnology companies, which are reflected within our disclosures included in Note 8, Fair Value Measurements, to these condensed consolidated financial statements, as well as venture capital funds where the underlying investments are in equity securities of certain biotechnology companies and non-marketable equity securities. As of March 31, 2026 and December 31, 2025, our strategic investment portfolio was comprised of investments totaling $ 205.3 million and $ 186.6 million, respectively, which are included in investments and other assets within our condensed consolidated balance sheets. The increase in our strategic investment portfolio as of March 31, 2026, compared to December 31, 2025, was primarily due to the increase in the fair value of our investment in Denali common stock. For additional information on our investments in Denali common stock, please read Note 8, Fair Value Measurements , and Note 17, Other Consolidated Financial Statement Detail , to these condensed consolidated financial statements. Note 10: Derivative Instruments Foreign Currency Forward Contracts - Hedging Instruments Due to the global nature of our operations, portions of our revenue and operating expense are recorded in currencies other than the U.S. dollar. The value of revenue and operating expense measured in U.S. dollars is therefore subject to changes in foreign currency exchange rates. We enter into foreign currency forward contracts and foreign currency options with financial institutions with the primary objective to mitigate the impact of foreign currency exchange rate fluctuations on our international revenue and operating expense. Foreign currency forward contracts and foreign currency options in effect as of March 31, 2026 and December 31, 2025, had durations of 1 to 18 months and 1 to 21 months, respectively. These contracts have been designated as cash flow hedges and unrealized gains and losses on the portion of these foreign currency forward contracts and foreign currency options that are included in the effectiveness test are reported in AOCI. Realized gains and losses of such contracts and options are recognized in revenue when the sale of product in the currency being hedged is recognized and in operating expense when the expense in the currency being hedged is recorded. We recognize all cash flow hedge reclassifications from AOCI and fair value changes of excluded portions in the same line item in our condensed consolidated statements of income that have been impacted by the hedged item. 26 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) The notional amount of foreign currency forward contracts and foreign currency options that were entered into to hedge forecasted revenue and operating expense is summarized as follows: Notional Amount (In millions) As of March 31, 2026 As of December 31, 2025 Euro $ 1,332.6 $ 1,531.0 Swiss franc 165.6 — British pound 76.2 — Polish zloty 33.0 — Canadian dollar 24.7 — Total foreign currency forward contracts and options $ 1,632.1 $ 1,531.0 The pre-tax portion of the fair value of these foreign currency forward contracts and foreign currency options that were included in AOCI in total equity is summarized as follows: (In millions) As of March 31, 2026 As of December 31, 2025 Unrealized gains $ 9.7 $ — Unrealized (losses) ( 24.4 ) ( 73.3 ) Net unrealized gains (losses) $ ( 14.7 ) $ ( 73.3 ) We expect net unrealized losses of approximately $ 14.7 million to be settled over the next 18 months, of which approximately $ 16.4 million of these net unrealized losses are expected to be settled over the next 12 months, with any amounts in AOCI to be reported as an adjustment to revenue or operating expense. We consider the impact of our and our counterparties’ credit risk on the fair value of the contracts as well as the ability of each party to execute its contractual obligations. As of March 31, 2026 and December 31, 2025, credit risk did not materially change the fair value of our foreign currency forward contracts and forward currency options. The following table summarizes the effect of foreign currency forward contracts and forward currency options designated as hedging instruments in our condensed consolidated statements of income: For the Three Months Ended March 31, Net Gains/(Losses) Reclassified from AOCI into Operating Income (in millions) Net Gains/(Losses) Excluded from Effectiveness Testing and Recognized in Operating Income (in millions) Location 2026 2025 Location 2026 2025 Revenue $ ( 24.3 ) $ 10.9 Revenue $ 4.1 $ 0.4 Operating expense 0.7 0.7 Operating expense ( 1.1 ) ( 1.0 ) Foreign Currency Forward Contracts - Other Derivative Instruments We also enter into other foreign currency forward contracts, usually with durations of one month or less, to mitigate the foreign currency risk related to certain balance sheet positions. We have not elected hedge accounting for these transactions. The aggregate notional amount of these outstanding foreign currency forward contracts was $ 1,241.1 million and $ 1,193.7 million as of March 31, 2026 and December 31, 2025, respectively. Net losses of $ 18.8 million related to these contracts was recorded as a component of other (income) expense, net for the three months ended March 31, 2026, compared to net gains of $ 7.7 million in the prior year comparative period. Summary of Derivative Instruments While certain of our derivative instruments are subject to netting arrangements with our counterparties, we do not offset derivative assets and liabilities in our condensed consolidated balance sheets. The amounts in the table below would not be substantially different if the derivative assets and liabilities were offset. 27 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) The following table summarizes the fair value and presentation in our condensed consolidated balance sheets of our outstanding derivative instruments, including those designated as hedging instruments: (In millions) Balance Sheet Location As of March 31, 2026 As of December 31, 2025 Cash Flow Hedging Instruments: Asset derivative instruments Other current assets $ 12.2 $ 0.1 Investments and other assets 5.9 0.4 Liability derivative instruments Accrued expense and other 12.2 54.0 Other long-term liabilities — 2.2 Other Derivative Instruments: Asset derivative instruments Other current assets 6.9 9.9 Liability derivative instruments Accrued expense and other 26.0 2.7 Note 11: Property, Plant and Equipment Property, plant and equipment are recorded at historical cost, net of accumulated depreciation. Accumulated depreciation on property, plant and equipment was $ 2,998.3 million and $ 2,931.2 million as of March 31, 2026 and December 31, 2025, respectively. For the three months ended March 31, 2026 and 2025, depreciation expense totaled approximately $ 67.9 million and $ 71.4 million, respectively. Note 12: Indebtedness 2025 Senior Notes On May 12, 2025, we issued senior unsecured notes for an aggregate principal amount of $ 1.75 billion, consisting of the following: • $ 400.0 million of 5.050 % Senior Notes due January 15, 2031, valued at 99.981 % of par; • $ 650.0 million of 5.750 % Senior Notes due May 15, 2035, valued at 99.924 % of par; and • $ 700.0 million of 6.450 % Senior Notes due May 15, 2055, valued at 99.657 % of par. Our 2025 Senior Notes are senior unsecured obligations and may be redeemed at our option at any time at 100 % of the principal amount plus accrued interest and, until a specified period before maturity, a specified make-whole amount. Our 2025 Senior Notes contain a change-of-control provision that, under certain circumstances, may require us to purchase our 2025 Senior Notes at a price equal to 101 % of the principal amount plus accrued and unpaid interest to the date of repurchase. We incurred approximately $ 13.9 million of costs associated with this offering which have been recorded as a reduction to the carrying amount of the debt on our condensed consolidated balance sheets. These costs will be amortized as additional interest expense using the effective interest rate method over the period from issuance through maturity. The discounts will be amortized as additional interest expense over the period from issuance through maturity using the effective interest rate method. Interest on our 2031 Senior Notes is payable January 15 and July 15 of each year, commencing January 15, 2026. Interest on our 2035 Senior Notes and 2055 Senior Notes is payable May 15 and November 15 of each year, commencing on November 15, 2025. 4.050% Senior Notes due September 15, 2025 On September 15, 2015, we issued $ 1.75 billion aggregate principal amount of 4.050 % Senior Notes due September 15, 2025, at 99.764 % of par. In June 2025 we used the net proceeds from the sale of our 2025 Senior Notes to redeem our 4.050 % Senior Notes due September 15, 2025, prior to maturity. No gain or loss was recognized upon redemption. 28 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Note 13: Equity Accumulated Other Comprehensive Income (Loss) The following tables summarize the changes in AOCI, net of tax by component: For the Three Months Ended March 31, 2026 (In millions) Unrealized Gains (Losses) on Securities Available for Sale, Net of Tax Unrealized Gains (Losses) on Cash Flow Hedges, Net of Tax Unrealized Gains (Losses) on Pension Benefit Obligation, Net of Tax Currency Translation Adjustments, Net of Tax Total Balance, December 31, 2025 $ 0.2 $ ( 58.9 ) $ ( 9.4 ) $ ( 113.9 ) $ ( 182.0 ) Other comprehensive income (loss) before reclassifications ( 1.8 ) 31.9 ( 0.5 ) ( 8.5 ) 21.1 Amounts reclassified from AOCI — 20.7 — — 20.7 Net current period other comprehensive income (loss) ( 1.8 ) 52.6 ( 0.5 ) ( 8.5 ) 41.8 Balance, March 31, 2026 $ ( 1.6 ) $ ( 6.3 ) $ ( 9.9 ) $ ( 122.4 ) $ ( 140.2 ) For the Three Months Ended March 31, 2025 (In millions) Unrealized Gains (Losses) on Cash Flow Hedges, Net of Tax Unrealized Gains (Losses) on Pension Benefit Obligation, Net of Tax Currency Translation Adjustments, Net of Tax Total Balance, December 31, 2024 $ 51.6 $ ( 16.6 ) $ ( 171.2 ) $ ( 136.2 ) Other comprehensive income (loss) before reclassifications ( 47.5 ) 0.4 19.1 ( 28.0 ) Amounts reclassified from AOCI ( 10.3 ) — — ( 10.3 ) Net current period other comprehensive income (loss) ( 57.8 ) 0.4 19.1 ( 38.3 ) Balance, March 31, 2025 $ ( 6.2 ) $ ( 16.2 ) $ ( 152.1 ) $ ( 174.5 ) The following table summarizes the amounts reclassified from AOCI: (In millions) Amounts Reclassified from AOCI Income Statement Location For the Three Months Ended March 31, 2026 2025 Gains (losses) on cash flow hedges $ ( 24.3 ) $ 10.9 Revenue 0.7 0.7 Operating expense — ( 0.1 ) Other (income) expense, net 2.9 ( 1.2 ) Income tax (benefit) expense Total reclassifications, net of tax $ ( 20.7 ) $ 10.3 29 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Note 14: Earnings per Share Basic and diluted shares outstanding used in our earnings per share calculation are calculated as follows: For the Three Months Ended March 31, (In millions) 2026 2025 Numerator: Net income attributable to Biogen Inc. $ 319.5 $ 240.5 Denominator: Weighted average number of common shares outstanding 147.2 146.1 Effect of dilutive securities: Time-vested restricted stock units 1.0 0.5 Performance stock units settled in stock 0.2 — Dilutive potential common shares 1.2 0.5 Shares used in calculating diluted earnings per share 148.4 146.6 Amounts excluded from the calculation of net income per diluted share because their effects were anti-dilutive were insignificant. Note 15: Share-Based Payments Share-based Compensation Expense The following table summarizes share-based compensation expense included in our condensed consolidated statements of income: For the Three Months Ended March 31, (In millions) 2026 2025 Research and development $ 34.8 $ 32.1 Selling, general and administrative 53.0 52.0 Subtotal 87.8 84.1 Capitalized share-based compensation costs ( 3.8 ) ( 3.1 ) Share-based compensation expense included in total cost and expense 84.0 81.0 Income tax effect ( 16.5 ) ( 16.0 ) Share-based compensation expense included in net income attributable to Biogen Inc. $ 67.5 $ 65.0 The following table summarizes share-based compensation expense associated with each of our share-based compensation programs: For the Three Months Ended March 31, (In millions) 2026 2025 Time-vested restricted stock units $ 70.9 $ 66.1 Performance stock units settled in stock 13.3 13.6 Employee stock purchase plan 3.6 3.5 Stock options — 0.9 Subtotal 87.8 84.1 Capitalized share-based compensation costs ( 3.8 ) ( 3.1 ) Share-based compensation expense included in total cost and expense $ 84.0 $ 81.0 30 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Note 16: Income Taxes Tax Rate For the three months ended March 31, 2026 and 2025, our effective tax rate was 15.4 % and 22.7 %, respectively. The decrease in our effective tax rate was partially driven by favorable impacts of a current year settlement of a foreign tax audit and the vesting of certain share based awards, partially offset by the higher rate of tax on NCTI due to the OBBBA enactment. Accounting for Uncertainty in Income Taxes We and our subsidiaries are routinely examined by various taxing authorities. We file income tax returns in various U.S. states and in U.S. federal and other foreign jurisdictions. With few exceptions, we are no longer subject to U.S. federal tax examination for years before 2022 or state, local or non-U.S. income tax examinations for years before 2013. It is reasonably possible that we will adjust the value of our uncertain tax positions related to certain transfer pricing, collaboration matters, withholding taxes and other issues as we receive additional information from various taxing authorities, including reaching settlements with such authorities. For additional information on our income taxes, please read Note 17, Income Taxes , to our consolidated financial statements included in our 2025 Form 10-K. Note 17: Other Consolidated Financial Statement Detail Other (Income) Expense, Net Components of other (income) expense, net, are summarized as follows: For the Three Months Ended March 31, (In millions) 2026 2025 Interest income $ ( 37.9 ) $ ( 23.9 ) Interest expense 67.6 60.0 (Gains) losses on investments, net ( 22.3 ) 35.6 Litigation related expense 4.7 3.0 Foreign exchange (gains) losses, net 6.5 ( 3.8 ) Other, net 1.1 ( 2.5 ) Total other (income) expense, net $ 19.7 $ 68.4 The (gains) losses on investments, net, as reflected in the table above, relate to debt securities, equity securities of certain biotechnology companies, venture capital funds where the underlying investments are in equity securities of certain biotechnology companies and non-marketable equity securities. The following table summarizes our (gains) losses on investments, net that relate to our equity securities held during the following periods: For the Three Months Ended March 31, (In millions) 2026 2025 Net (gains) losses recognized on equity securities $ ( 22.3 ) $ 35.6 Less: Net (gains) losses realized on equity securities ( 3.2 ) ( 5.4 ) Net unrealized (gains) losses recognized on equity securities $ ( 19.1 ) $ 41.0 The net unrealized gains recognized during the three months ended March 31, 2026, primarily reflect an increase in the aggregate fair value of our investment in Denali common stock of approximately $ 19.2 million. The net unrealized losses recognized during the three months ended March 31, 2025, primarily reflect a decrease in the aggregate fair value of our investment in Denali common stock of approximately $ 48.5 million, partially offset by an increase in the fair value of Sage common stock of approximately $ 15.7 million, which was later disposed of during the third quarter of 2025. 31 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Other Current Assets Other current assets includes prepaid taxes of $ 661.6 million and $ 693.6 million as of March 31, 2026 and December 31, 2025, respectively. Accrued Expense and Other Accrued expense and other consists of the following: (In millions) As of March 31, 2026 As of December 31, 2025 Revenue-related reserves for discounts and allowances $ 961.1 $ 1,000.4 Employee compensation and benefits 192.5 375.8 Collaboration expense 353.5 280.0 Royalties and licensing fees 308.5 302.4 Other 731.2 844.0 Total accrued expense and other $ 2,546.8 $ 2,802.6 Other Long-term Liabilities Other long-term liabilities were $ 787.1 million and $ 748.5 million as of March 31, 2026 and December 31, 2025, respectively, and included accrued income taxes totaling $ 174.2 million and $ 166.4 million, respectively . Note 18: Collaborative and Other Relationships Genentech, Inc. (Roche Group) We have certain business and financial rights with respect to RITUXAN for the treatment of non-Hodgkin's lymphoma, CLL and other conditions; RITUXAN HYCELA for the treatment of non-Hodgkin's lymphoma and CLL; GAZYVA for the treatment of CLL, follicular lymphoma and lupus nephritis; OCREVUS for the treatment of PPMS and RMS; LUNSUMIO for the treatment of relapsed or refractory follicular lymphoma; COLUMVI, a bispecific antibody for the treatment of non-Hodgkin's lymphoma; and have the option to add other potential anti-CD20 therapies, pursuant to our collaboration arrangements with Genentech, a wholly owned member of the Roche Group. For purposes of this footnote, we refer to RITUXAN and RITUXAN HYCELA collectively as RITUXAN. RITUXAN Under our collaboration with Genentech, we are entitled to a tiered share of co-promotion operating profits and losses of RITUXAN in the U.S., as summarized in the table below. Genentech and its affiliates are responsible for the worldwide manufacture of RITUXAN as well as all development and commercialization activities as follows: • U.S.: We have co-exclusively licensed our rights to develop, commercialize and market RITUXAN in the U.S. • Canada: We have co-exclusively licensed our rights to develop, commercialize and market RITUXAN in Canada. GAZYVA The Roche Group and its sub-licensees maintain sole responsibility for the development, manufacture and commercialization of GAZYVA and we are entitled to a tiered share of co-promotion operating profits and losses of GAZYVA in the U.S. The level of gross sales of GAZYVA in the U.S. has impacted our percentage of the co-promotion profits for RITUXAN and LUNSUMIO, as summarized in the table below. OCREVUS Pursuant to the terms of our collaboration arrangements with Genentech, we receive a tiered royalty on U.S. net sales from 13.5 % and increasing up to 24.0 % if annual net sales exceed $ 900.0 million. There will be a 50.0 % reduction to these royalties upon the first entry of an FDA-approved biosimilar to OCREVUS. In addition, we receive a gross 3.0 % royalty on net sales of OCREVUS outside the U.S., with the royalty period lasting 11 years from the first commercial sale of OCREVUS on a country-by-country basis. The commercialization of OCREVUS does not impact the percentage of the co-promotion profits we receive for RITUXAN, LUNSUMIO or GAZYVA. Genentech is solely responsible for development and commercialization of 32 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) OCREVUS and funding future costs. Genentech cannot develop OCREVUS in CLL, non-Hodgkin's lymphoma or rheumatoid arthritis. OCREVUS royalty revenue is based on our estimates from third party and market research data of OCREVUS sales occurring during the corresponding period. Differences between actual and estimated royalty revenue will be adjusted for in the period in which they become known, which is generally expected to be the following quarter. LUNSUMIO Under our collaboration with Genentech, we are entitled to a tiered share of co-promotion operating profits and losses in the U.S., as summarized in the table below. In addition, we receive low-single digit royalties on sales of LUNSUMIO outside the U.S. COLUMVI Genentech has sole decision-making rights on the commercialization of COLUMVI within the U.S. and we receive tiered royalties in the mid-single digit range on net sales of COLUMVI in the U.S. The commercialization of COLUMVI does not impact the percentage of the co-promotion profits we receive for RITUXAN, LUNSUMIO or GAZYVA. Profit-sharing Formulas RITUXAN and LUNSUMIO Profit Share Our current pre-tax co-promotion profit-sharing formula for RITUXAN and LUNSUMIO in the U.S. provides for a 30.0 % share on the first $ 50.0 million of combined co-promotion operating profits earned each calendar year. Our share of the combined annual co-promotion profits for RITUXAN and LUNSUMIO in excess of $ 50.0 million varies upon the following events, as summarized in the table below: After LUNSUMIO Approval until the First Threshold Date 37.5 % After First Threshold Date until the Second Threshold Date 35.0 % After Second Threshold Date 30.0 % In March 2023 the First Threshold Date was achieved when U.S. gross sales of GAZYVA within a consecutive 12-month period reached $ 500.0 million. As a result, beginning in April 2023 the pre-tax profit share for RITUXAN and LUNSUMIO has been 35.0 %. The Second Threshold Date would be achieved on the first date in any calendar year in which U.S. gross sales of LUNSUMIO have reached $ 350.0 million. GAZYVA Profit Share Our current pre-tax profit-sharing formula for GAZYVA provides for a 35.0 % share of operating profits earned in the U.S. in each calendar year. For additional information on our collaboration arrangements with Genentech, please read Note 19, Collaborative and Other Relationships , to our consolidated financial statements included in our 2025 Form 10-K. Ionis Pharmaceuticals, Inc. 2017 SMA Collaboration Agreement In December 2017 we entered into a collaboration agreement with Ionis to identify new ASO drug candidates for the potential treatment of SMA. Under this agreement, we have options to license therapies arising out of this collaboration and will be responsible for the development and commercialization of such therapies. In December 2021 we exercised our option with Ionis and obtained a worldwide, exclusive, royalty-bearing license to develop and commercialize salanersen (BIIB115), an investigational ASO in development for SMA. We may pay Ionis up to $ 155.0 million in additional development and regulatory milestone payments related to salanersen, including a $ 45.0 million milestone payment due upon the initiation of a Phase 3 trial. Upon commercialization, we may also pay Ionis up to $ 400.0 million in additional performance-based milestone payments and tiered royalties on potential net sales of such therapies ranging from the mid-teens to high-twenties percentages. 33 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) For additional information on our collaboration arrangements with Ionis, please read Note 19, Collaborative and Other Relationships , to our consolidated financial statements included in our 2025 Form 10-K. Eisai Co., Ltd. LEQEMBI (lecanemab) Collaboration We have a collaboration agreement with Eisai to jointly develop and commercialize LEQEMBI (lecanemab), an anti-amyloid antibody for the treatment of Alzheimer's disease. The FDA granted traditional approval of LEQEMBI in July 2023. Prior to receiving traditional approval, LEQEMBI had been granted accelerated approval by the FDA in January 2023, at which time it became commercially available in the U.S. Outside of the U.S., LEQEMBI is now approved in the E.U. (April 2025), Australia (September 2025), China (January 2024), Japan (September 2023) and other international markets. LEQEMBI monthly IV maintenance dosing for the treatment of early Alzheimer's disease was approved in the U.S. and China in January 2025 and September 2025, respectively, and LEQEMBI subcutaneous autoinjector (IQLIK) for weekly maintenance dosing was approved in the U.S. in August 2025. All costs, including research, development, sales and marketing expense, are shared equally between us and Eisai. We also share profits and losses equally. We currently have a supply agreement with Eisai to manufacture LEQEMBI drug substance and drug product through the end of 2031. Subject to the limitations in the LEQEMBI Collaboration Agreement, Eisai has final decision-making authority on all matters relating to the collaboration and serves as the lead of LEQEMBI development and regulatory submissions globally. We co-commercialize and co-promote LEQEMBI with Eisai. The LEQEMBI Collaboration Agreement provides that each commercialization plan shall allocate the responsibilities for the activities under the plan in an equitable fashion taking into account Biogen's and Eisai's respective capabilities and provides a meaningful role for each party. Upon commercialization of LEQEMBI in the U.S., we began recognizing our 50.0 % share of LEQEMBI product revenue, net and cost of sales, including royalties, within Alzheimer's collaboration revenue in our condensed consolidated statements of income, as we are not the principal. Our share of LEQEMBI sales and marketing expense and development expense are recorded within selling, general and administrative expense and research and development expense, respectively, within our condensed consolidated statements of income. A summary of development and sales and marketing expense related to the LEQEMBI Collaboration is as follows: For the Three Months Ended March 31, (In millions) 2026 2025 Total development expense incurred by the collaboration related to the advancement of LEQEMBI $ 69.3 $ 52.6 Biogen's share of the LEQEMBI Collaboration development expense reflected in research and development expense in our condensed consolidated statements of income 34.6 26.3 Total sales and marketing expense incurred by the LEQEMBI Collaboration 169.5 177.7 Biogen's share of the LEQEMBI Collaboration sales and marketing expense reflected in selling, general and administrative expense in our condensed consolidated statements of income 84.7 88.8 Amounts receivable from Eisai related to the agreements discussed above were approximately $ 7.0 million and $ 90.2 million as of March 31, 2026 and December 31, 2025, respectively. Amounts payable to Eisai related to the agreements discussed above were approximately $ 85.4 million and $ 95.5 million as of March 31, 2026 and December 31, 2025, respectively. For additional information on our collaboration arra ngements with Eisai, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in our 2025 Form 10-K. UCB We have a collaboration agreement with UCB, effective November 2003, to jointly develop and commercialize dapirolizumab pegol, an anti-CD40L pegylated Fab, for the potential treatment of SLE and other future agreed indications. Either we or UCB may propose development of dapirolizumab pegol in additional indications. If the parties do not agree to add an indication as an agreed indication to the collaboration, we or UCB may, at the sole expense of the applicable party, pursue development in such excluded indication(s), subject to an opt-in right of the non-pursuing party after proof of clinical activity. 34 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) All costs incurred for agreed indications, including research, development, sales and marketing expense, are shared equally between us and UCB. If marketing approval is obtained, both companies will jointly commercialize dapirolizumab pegol and share profits and losses equally. A summary of development expense related to the UCB collaboration agreement is as follows: For the Three Months Ended March 31, (In millions) 2026 2025 Total UCB collaboration development expense $ 29.4 $ 21.8 Biogen's share of the UCB collaboration development expense reflected in research and development expense in our condensed consolidated statements of income 14.7 10.9 Supernus Pharmaceuticals, Inc. (previously Sage Therapeutics, Inc.) In November 2020 we entered into a global collaboration and license agreement with Sage to jointly develop and commercialize ZURZUVAE (zuranolone) for the treatment of PPD. In July 2025 Sage was acquired by Supernus. ZURZUVAE was approved in the U.S. in August 2023 and in the E.U. in September 2025. Under this collaboration, both companies will share equal responsibility and costs for development as well as profits and losses for commercialization in the U.S. Outside of the U.S., we are responsible for development and commercialization, excluding Japan, Taiwan and South Korea, with respect to zuranolone and may pay Supernus potential tiered royalties in the high-teens to low-twenties percentages. We share 50.0 % of the net collaboration results in the U.S. with Supernus, which are recognized in collaboration profit sharing/(loss reimbursement) in our condensed consolidated statements of income. For the three months ended March 31, 2026 and 2025, we recognized net profit-sharing expense of approximately $ 17.0 million and $ 10.1 million, respectively, to reflect Supernus' 50.0 % share of the net collaboration results in the U.S. A summary of development and sales and marketing expense related to the Supernus collaboration is as follows: For the Three Months Ended March 31, (In millions) 2026 2025 Total Supernus collaboration development expense $ 1.2 $ 2.4 Biogen's share of the Supernus collaboration development expense reflected in research and development expense in our condensed consolidated statements of income 0.6 1.2 Total sales and marketing expense incurred by the Supernus collaboration 47.5 43.5 Biogen's share of the Supernus collaboration sales and marketing expense reflected in selling, general and administrative expense and collaboration profit sharing/(loss reimbursement) in our condensed consolidated statements of income 23.7 21.7 Denali Therapeutics Inc. In August 2020 we entered into a collaboration and license agreement with Denali to co-develop and co-commercialize BIIB122, a small molecule inhibitor of LRRK2 for Parkinson's disease (LRRK2 Collaboration). Under the LRRK2 Collaboration, both companies share responsibility and costs for global development based on specified percentages as well as profits and losses for commercialization in the U.S. and China. Outside the U.S. and China we are responsible for commercialization and may pay Denali potential tiered royalties. A summary of development expense related to the Denali collaboration is as follows: For the Three Months Ended March 31, (In millions) 2026 2025 Total Denali collaboration development expense $ 10.3 $ 12.8 Biogen's share of the Denali collaboration development expense reflected in research and development expense in our condensed consolidated statements of income 6.2 7.7 Stoke Therapeutics, Inc. In February 2025 we entered into a collaboration and license agreement with Stoke to co-develop and commercialize zorevunersen, an investigational ASO that targets the SCN1A gene for the potential treatment of Dravet syndrome, a rare form of genetic epilepsy associated with refractory seizures and neurodevelopmental impairments. Zorevunersen dosed its first patient in August 2025, advancing zorevunersen to a global Phase 3 trial. 35 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Under the terms of this agreement, Stoke will continue to lead global development and retain exclusive development and commercialization rights for zorevunersen in the U.S., Canada and Mexico and we will have exclusive rights to commercialize zorevunersen in the rest of the world. Both companies will share responsibility for external clinical development costs, where Stoke is responsible for 70.0 % of these development costs and we are responsible for the remaining 30.0 % of these development costs. In connection with the closing of this transaction we made an upfront payment of $ 165.0 million to Stoke, which was recognized in acquired in-process research and development, upfront and milestone expense within our condensed consolidated statements of income for the three months ended March 31, 2025. We may also pay Stoke potential development and commercial milestone payments of up to $ 50.0 million and $ 335.0 million, respectively, if all the specified milestones set forth in this collaboration are achieved. In addition, we may pay Stoke tiered royalties on potential net sales of any products developed under this collaboration in the low-double digit to high-teen percentages. We also have an exclusive option to license certain future follow-on ASO products targeting the SCN1A gene in all territories worldwide other than the U.S., Canada and Mexico, in exchange for separate milestone, cost sharing and royalty considerations. A summary of development expense related to the Stoke collaboration agreement is as follows: For the Three Months Ended March 31, (In millions) 2026 2025 Total Stoke collaboration development expense $ 12.2 $ 3.9 Biogen's share of the Stoke collaboration development expense reflected in research and development expense in our condensed consolidated statements of income 3.7 1.2 Samsung Bioepis Co., Lt d. 2019 Development and Commercialization Agreement In December 2019 we completed a transaction with Samsung Bioepis and secured the exclusive rights to commercialize two potential ophthalmology biosimilar products, BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, and OPUVIZ, an aflibercept biosimilar referencing EYLEA, in major markets worldwide, including the U.S., Canada, Europe, Japan and Australia. The agreement established that Samsung Bioepis will be responsible for development and will supply both products to us at a pre-specified gross margin of approximately 45.0 %. In October 2024 we notified Samsung Bioepis of our decision to terminate our 2019 Development and Commercialization Agreement (the DCA Agreement) solely within the U.S. and Canada. The transfer of commercialization rights for BYOOVIZ and OPUVIZ in the U.S. and Canada back to Samsung Bioepis was completed as of December 31, 2025. In October 2025 we completed the sale of our remaining commercial rights to BYOOVIZ and OPUVIZ in Europe. Samsung Bioepis will have full responsibility for commercialization of BYOOVIZ upon the transfer of commercial rights from Biogen back to Samsung Bioepis, which became effective as of January 2026. We reflected revenue on sales of BYOOVIZ to third parties in product revenue, net in our condensed consolidated statements of income and recorded the related cost of revenue and sales and marketing expense in our condensed consolidated statements of income to their respective line items when these costs are incurred. 2013 Commercial Agreement In December 2013 we entered into an agreement with Samsung Bioepis to commercialize, over a 10-year term, three anti-TNF biosimilar product candidates which includes IMRALDI, an adalimumab biosimilar referencing HUMIRA, FLIXABI, an infliximab biosimilar referencing REMICADE, and BENEPALI, an etanercept biosimilar referencing ENBREL, in Europe. In July 2024 we exercised an option to extend this agreement by an additional five years . We reflect revenue on sales of BENEPALI, IMRALDI and FLIXABI to third parties in product revenue, net in our condensed consolidated statements of income and record the related cost of revenue and sales and marketing expense in our condensed consolidated statements of income to their respective line items when these costs are incurred. Royalty payments to AbbVie on sales of IMRALDI are recognized in cost of sales within our condensed consolidated statements of income. 36 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) We share 50.0 % of the profit or loss related to our 2013 commercial agreement with Samsung Bioepis, which is recognized in collaboration profit sharing/(loss reimbursement) in our condensed consolidated statements of income. For the three months ended March 31, 2026 and 2025, we recognized net profit-sharing expense of approximately $ 57.2 million and $ 48.0 million, respectively, to reflect Samsung Bioepis' 50.0 % sharing of the net collaboration profits. Other Services Simultaneous with the formation of Samsung Bioepis, we also entered into a license agreement with Samsung Bioepis. Under this license agreement, we granted Samsung Bioepis an exclusive license to use, develop, manufacture and commercialize biosimilar products created by Samsung Bioepis using Biogen product-specific technology. In exchange, we receive single-digit royalties on biosimilar products developed and commercialized by Samsung Bioepis. Royalty revenue under the license agreement is recognized as a component of contract manufa cturing, royalty and other revenue in our condensed consolidated statements of income. Amounts receivable from Samsung Bioepis related to the agreements discussed above were approximately $ 4.7 million and $ 4.4 million as of March 31, 2026 and December 31, 2025, respectively. Amounts payable to Samsung Bioepis related to the agreements discussed above were approximately $ 154.4 million and $ 42.7 million as of March 31, 2026 and December 31, 2025, respectively. For additional information on our collaboration arrangements with Samsung Bioepis and our other significant collaboration arrangements, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in our 2025 Form 10-K. Other Research and Discovery Arrangements and Funding Arrangements These arrangements may include the potential for future milestone payments based on the achievement of certain clinical and commercial development payable over a period of several years. Other For the three months ended March 31, 2026 and 2025, we recorded approximately $ 34.0 million and less than $ 1.0 million, respectively, as acquired in-process research and development, upfront and milestone expense in our condensed consolidated statements of income related to other research and discovery related arrangements. Royalty Pharma Funding Arrangement In February 2025 we entered into a funding agreement with Royalty Pharma under which we received $ 200.0 million in 2025 and $ 50.0 million in 2026 to co-fund our development costs for the litifilimab program. As there is a substantive transfer of risk to the financial partner for the amount invested, the development funding will be recognized by us as an obligation to perform contractual services. This funding is being recognized as a reduction to research and development expense within our condensed consolidated statements of income, proportionate to the related expen se. For the three months ended March 31, 2026 and 2025, we received $ 25.0 million and $ 50.0 million, respectively, from Royalty Pharma, which we recorded as reductions to research and development expense within our condensed consolidated statements of income. The final payment related to the funding agreement of $25.0 million was received in April 2026. If the litifilimab clinical trials are successful for the indications based on the applicable clinical trials, upon regulatory approval in the U.S. or certain major markets in the world, Royalty Pharma will be eligible to receive approval-based fixed milestone payments of up to $ 250.0 million. The milestone payments due upon approval will be recorded as a component of other (income) expense, net within our condensed consolidated statements of income, when incurred. If litifilimab receives regulatory approval, Royalty Pharma will be eligible to receive royalties of a mid-single digit percentage of the applicable net sales. Royalties on net sales will be recorded as cost of sales within our condensed consolidated statements of income. 37 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) MorphoSys AG As part of our acquisition of HI-Bio in July 2024, we acquired HI-Bio's pre-existing in-license commitments under third-party agreements with MorphoSys, which included tiered royalties on potential future sales ranging from high-single digit to mid-teen percentages, as well as potential development, regulatory and commercial milestone payments of up to $ 130.0 million, $ 230.0 million and $ 640.0 million, respectively. These amounts included milestone payments due upon the first patient dosed in a Phase 3 clinical trial of felzartamab in a first and second indication of $ 35.0 million and $ 30.0 million, respectively. In April 2026 we entered into a definitive agreement with TJ Bio, where we assumed regulatory and sales milestone obligations under a pre-existing agreement between TJ Bio and MorphoSys and may pay MorphoSys tiered royalties on potential net sales of felzartamab in the greater China region. For additional information on TJ Bio, please read Note 22, Subsequent Events , to these condensed consolidated financial statements. During the first quarter of 2025 we accrued a milestone payment due to MorphoSys of $ 35.0 million upon the first patient dosed in a Phase 3 clinical trial of felzartamab for the treatment of AMR, which was recorded within acquired in-process research and development, upfront and milestone expense in our condensed consolidated statements of income for the three months ended March 31, 2025, and paid in April 2025. During the second quarter of 2025 we accrued a milestone payment due to MorphoSys of $ 30.0 million upon the first patient dosed in a Phase 3 clinical trial of felzartamab for the treatment of IgAN, which was recorded within acquired in-process research and development, upfront and milestone expense in our condensed consolidated statements of income, and paid in July 2025. Note 19: Investments in Variable Interest Entities Unconsolidated Variable Interest Entities We have relationships with various variable interest entities that we do not consolidate as we lack the power to direct the activities that significantly impact the economic success of these entities. These relationships include investments in certain biotechnology companies and research collaboration agreements. As of March 31, 2026 and December 31, 2025, the carrying value of our investments in certain biotechnology companies representing potential unconsolidated variable interest entities totaled $ 48.4 million and $ 49.8 million, respectively. Our maximum exposure to loss related to these variable interest entities is limited to the carrying value of our investments. We have also entered into research collaboration agreements with certain variable interest entities where we are required to fund certain development activities. These development activities are included in research and development expense in our condensed consolidated statements of income as they are incurred. We have provided no financing to these variable interest entities other than previous contractually required amounts. For additional information on our investments in variable interest entities, please read Note 20, Investments in Variable Interest Entities, to our consolidated financial statements included in our 2025 Form 10-K. Note 20: Litigation We are currently involved in various claims, investigations and legal proceedings, including the matters described below. For information as to our accounting policies relating to claims and legal proceedings, including use of estimates and contingencies, please read Note 1, Summary of Significant Accounting Policies, to our consolidated financial statements included in our 2025 Form 10-K. With respect to some loss contingencies, an estimate of the possible loss or range of loss cannot be made until management has further information, including, for example, (i) which claims, if any, will survive dispositive motion practice; (ii) information to be obtained through discovery; (iii) information as to the parties' damages claims and supporting evidence; (iv) the parties’ legal theories; and (v) the parties' settlement positions. If an estimate of the possible loss or range of loss can be made at this time, it is included in the potential loss contingency description below. The claims and legal proceedings in which we are involved also include challenges to the scope, validity or enforceability of the patents relating to our products, pipeline or processes and challenges to the scope, validity or 38 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) enforceability of the patents held by others. These include claims by third parties that we infringe their patents. An adverse outcome in any of these proceedings could result in one or more of the following and have a material impact on our business or consolidated results of operations and financial position: (i) loss of patent protection; (ii) inability to continue to engage in certain activities; and (iii) payment of significant damages, royalties, penalties and/or license fees to third parties. Loss Contingencies Securities Litigation We and certain current and former officers are defendants in three securities actions pending in the District Court, one filed by Nadia Shash and Amjad Khan in November 2020, which relates to statements about ADUHELM, one filed by the Oklahoma Firefighters Pension and Retirement System in February 2022, which relates to statements about ADUHELM, and one filed by Thomas Allen Gray and Frances Clarity Stokes in May 2024, which relates to statements about LEQEMBI, TECFIDERA and VUMERITY. All allege violations of federal securities laws under 15 U.S.C. §78j(b) and §78t(a) and 17 C.F.R. §240.10b-5 and seek declarations of the actions as class actions and monetary relief. In March 2026 the District Court dismissed the action brought by Thomas Allen Gray and Frances Clarity Stokes and they have appealed. In April 2026 the parties in the action brought by the Oklahoma Firefighters Pension and Retirement System reached an agreement in principle to settle the action. Derivative Actions We and members of the Board of Directors are named as defendants in five derivative actions pending in the District Court, one filed by The Booth Family Trust (Booth) in February 2022, one filed by Elaine Wang (Wang) in July 2022, one filed by Jonathan Blaufarb (Blaufarb I) in July 2024, one filed by Lawrence Hollin (Hollin) in October 2024 and one filed by Jonathan Blaufarb (Blaufarb II) in October 2024. The Booth, Wang and Blaufarb II actions relate to ADUHELM and other matters, and the Blaufarb I and Hollin actions relate to statements about LEQEMBI, our compliance controls, 2023 earnings guidance and other matters. The actions allege breach of fiduciary duty, waste of corporate assets and other common law claims, and violations of the Securities Exchange Act of 1934, 15 U.S.C. §78a et seq. The actions seek declaratory and injunctive relief, monetary relief payable to Biogen, and attorneys’ fees and costs payable to the plaintiffs. All derivative actions are stayed. IMRALDI Patent Litigation IMRALDI is an adalimumab biosimilar manufactured by Samsung Bioepis that Biogen commercializes in Europe. Fresenius Kabi has alleged infringement of national counterparts of its EP '3 145 488 Patent (the EP '488 Patent), including in Spain, Italy, France and Germany. In June 2022, Fresenius Kabi filed a claim for damages and injunctive relief against Biogen France SAS in the Tribunal de Grande Instance de Paris alleging infringement of the French counterpart of the EP '488 Patent by a formulation of IMRALDI no longer commercialized in France. Fresenius Kabi alleges damages of approximately € 19.1 million plus interest and costs. Biogen disputes infringement and the validity of the patent. Trial is set for June 2026. In May 2025 the Higher Regional Court of Düsseldorf, Germany held that a formulation of IMRALDI we no longer commercialize in Germany infringed the German counterpart of the EP '488 Patent, enjoined infringement and declared Fresenius Kabi's right to seek damages. Biogen has requested review of the decision by Germany's Federal Court of Justice and has challenged the validity of the patent in a separate proceeding. Humana Patient Assistance Litigation In February 2025 Humana filed suit against Biogen Inc., Biogen U.S. Corp. and Advanced Care Scripts, Inc. in Jefferson Circuit Court in Kentucky alleging damages related to providing MS patients with free medications and to charitable contributions to non-profit organizations that provide financial assistance to MS patients. Humana alleges breach of contract, fraud and other claims under various state laws and seeks damages, attorneys' fees and costs. Genentech Litigation In February 2023 Genentech Inc. filed suit in the U.S. District Court for the Northern District of California claiming that it was owed royalties on sales of TYSABRI that occurred after the expiration of a patent licensed by Genentech to Biogen. In November 2025 the court entered judgment against us for approximately $ 124.3 million. We appealed and the appeal is pending. 39 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Antitrust Litigation In October 2025 Local No. 1 Health Fund, the Mayor and City Council of Baltimore, Teamsters Local 237 Welfare Fund, Teamsters Local 237 Retirees' Benefit Fund, UFCW Local 1500 Welfare Fund, and Jacksonville Police Officers and Fire Fighters Health Insurance Trust filed an amended complaint against us in now consolidated proceedings in the U.S. District Court for the Northern District of Illinois (the Illinois federal court). The first complaint was filed in August 2024. The plaintiffs allege violations of federal antitrust laws including 15 U.S.C. §§ 1, 2 and 13(c), the Racketeer Influenced and Corrupt Organizations Act, 18 U.S.C. §1962(c) and of various state laws, based on allegations about our contracts with pharmacy benefit managers related to TECFIDERA and VUMERITY and other allegations. Plaintiffs seek declarations of the actions as class actions, monetary, declaratory and equitable relief, and attorneys' fees and costs. In addition, in September 2025 Walgreen Co. and The Kroger Co. sued us in the Illinois federal court, alleging violations of 15 U.S.C. §§ 1 and 2 based on allegations about our contracts with pharmacy benefit managers related to TECFIDERA and VUMERITY and other allegations. They seek monetary, declaratory and equitable relief, and attorneys' fees and costs. Neurimmune Litigation In May 2025 we sued Neurimmune Holding AG and Neurimmune Subone AG (collectively, "Neurimmune") in the District Court seeking declaratory judgment and permanent injunctive relief regarding our rights under a terminated collaboration agreement related to aducanumab. In September 2025 Neurimmune counterclaimed for declaratory judgment, breach of contract and unfair competition under Massachusetts G.L. 93A and seeking monetary, declaratory and equitable relief and attorneys' fees and costs. TECFIDERA E.U. Litigation We have sued certain generic companies for damages for sales of generic versions of TECFIDERA in violation of our regulatory market protection, including Neuraxpharm Pharmaceuticals S.L., Neuraxpharm Netherlands B.V., Zaklady Farmaceutyczne Polpharma S.A., Sandoz B.V., Mylan Ireland Ltd. and Mylan B.V. in the District Court of Amsterdam Netherlands in November 2023; Sandoz A/S in the Danish Maritime and Commercial High Court in June 2024; and STADA Arzneimittel AG, STADA Nordic ApS, Sandoz A/S, Sandoz (Denmark) and Sandoz A/S (Finland), Glenmark Arzneimittel AG and Glenmark Pharmaceuticals Nordic AB in the Finnish Market Court in July 2024. All of these parties have counterclaimed for damages based on our actions to enforce TECFIDERA's regulatory marketing protection. In September 2025 the European General Court annulled the May 2023 European Commission decision granting TECFIDERA an additional year of regulatory marketing protection extending until February 2025. We and the European Commission appealed and the appeal is pending. In November 2025 the Technical Boards of Appeal of the European Patent Office revoked our EP 2 653 873 patent related to TECFIDERA, after which we stopped enforcing this patent and its national counterparts. Certain generic companies have filed claims in the Danish Maritime and Commercial High Court for alleged damages due to injunctions we obtained prior to patent revocation, including Sandoz A/S in October 2025, Viatris ApS in January 2024, Glenmark Pharmaceuticals Nordic AB in July 2025 and Neuraxpharm Sweden AB and Neuraxpharm Pharmaceuticals S.L. in February 2026. Germany Tax Matter In December 2025 and January 2026 a German tax authority issued assessments against us of approximately € 209.8 million including interest, which continues to accrue. We are challenging the assessments. Other Matters Government Investigations In May 2024 the Italian Competition Authority informed us that it is investigating Biogen and other companies in relation to our biosimilar product BYOOVIZ. In September 2025 we received a Civil Investigative Demand from the Louisiana Department of Justice for information regarding our policies relating to the purchase of drugs by healthcare organizations that are covered entities under Section 340B of the Public Health Service Act. 40 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) In January 2026 we received a request for information regarding TECFIDERA from the European Commission Directorate-General for Competition. TYSABRI Biosimilar Patent Matter In September 2022 we filed an action in the U.S. District Court for the District of Delaware against Sandoz Inc., other Sandoz entities and Polpharma Biologics S.A. under the Biologics Price Competition and Innovation Act, 42 U.S.C. §262, seeking a declaratory judgment of patent infringement. Trial against Sandoz Inc. is scheduled for April 2027. Eisai Matter In June 2025 we filed a request for arbitration in the International Court of Arbitration of the International Chamber of Commerce seeking adoption of a budget and commercialization plan for the European Territory that allocates commercialization activities to Biogen and Eisai in an equitable fashion taking into account our respective capabilities and provides a meaningful role for each party. Product Liability and Other Legal Proceedings We are also involved in product liability claims and other legal proceedings incidental to our normal business activities. While the outcome of any of these proceedings cannot be accurately predicted, we do not believe the ultimate resolution of any of these existing matters would have a material adverse effect on our business or financial condition. Note 21: Segment Information We operate and are managed as one operating segment, and derive revenue from activities related to the discovery, development and delivery of innovative therapies for people living with serious and complex diseases. Our research and development organization is responsible for the research and discovery of new product candidates and supports development and registration efforts for potential future products. Our pharmaceutical, operations and technology organization manages the development of the manufacturing processes, clinical trial supply, commercial product supply, distribution, buildings and facilities. Our commercial organization is responsible for U.S. and international development of our commercial products. We are also supported by corporate staff functions. Our CEO, as the CODM, manages and allocates resources to the operations of our company on a total company basis by assessing the overall level of resources available and deciding how to best deploy these resources across functions, therapeutic areas and research and development projects that are in line with our long-term company-wide strategic goals. In making these decisions, our CEO is provided with and uses consolidated financial information for purposes of evaluating performance, forecasting future period financial results, allocating resources and setting incentive targets. The CODM performs this assessment based on the segment’s net income. Through this analysis, which includes a comparison to budgeted results, the CODM assesses performance and how to allocate resources across the functions discussed above. The measure of segment assets used in determining how to manage and allocate resources is reported within our condensed consolidated balance sheets as total assets. The table presented below, which was prepared in accordance with the accounting policies discussed in Note 1, Summary of Significant Accounting Policies , to our consolidated financial statements included in our 2025 Form 10-K, contains additional information on our segment’s revenue and profits, including significant segment expense and other segment items. 41 Table of Contents BIOGEN INC. AND SUBSIDIARIES NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited, continued) Additional Segment Information The following table includes additional information about reported segment revenue, significant segment expense and segment measure of profitability: For the Three Months Ended March 31, (In millions) 2026 2025 Total revenue $ 2,477.8 $ 2,431.0 Less cost and expense: Cost of sales, excluding amortization and impairment of acquired intangible assets: Product cost of sales 478.7 462.2 Royalty cost of sales 182.3 167.1 Research and development: Research and discovery 40.5 44.3 Early stage programs 69.0 72.4 Late stage programs 102.5 49.4 Marketed products 154.2 89.5 Other research and development costs (1) 172.8 178.5 Acquired in-process research and development, upfront and milestone expense 34.0 200.7 Selling, general and administrative 607.3 572.5 Other segment expense (2) 317.0 353.9 Net Income attributable to Biogen Inc. $ 319.5 $ 240.5 (1) Other research and development costs primarily consist of indirect costs incurred in support of overall research and development activities and non-specific programs, including activities that benefit multiple programs, such as management costs, as well as depreciation, information technology and facility-based expenses and are not allocated to a specific program or stage. (2) Other segment expense includes: amortization and impairment of acquired intangible assets; collaboration profit sharing/(loss reimbursement); (gain) loss on fair value remeasurement of contingent consideration; restructuring charges; other (income) expense, net; and income tax (benefit) expense . Note 22: Subsequent Events TJ Biopharma Co., Ltd. In April 2026 we entered into a definitive agreement with TJ Biopharma Co., Ltd. to acquire TJ Bio's exclusive rights to felzartamab in the greater China region. With this agreement, we will own exclusive worldwide rights to felzartamab. Under the terms of this agreement we made an upfront payment of $ 100.0 million to TJ Bio, which will be recognized in acquired in-process research and development, upfront and milestone expense within our condensed consolidated statements of income during the second quarter of 2026. T J Bio will also be eligible to receive potential commercial and sales milestone payments of up to $ 20.0 million and $ 730.0 million, respectively, if all specified milestones set forth in this collaboration are achieved. In addition, we may pay TJ Bio tiered royalties on potential net sales of felzartamab in the greater China region in the mid-single digit to low-double digit percentages. Additionally, we assumed regulatory and sales milestone obligations under a pre-existing agreement between TJ Bio and MorphoSys and may pay MorphoSys tiered royalties on potential net sales of felzartamab in the greater China region. 42 Table of Content ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS The following discussion should be read in conjunction with our unaudited condensed consolidated financial statements (condensed consolidated financial statements) and the accompanying notes beginning on page 8 of this quarterly report on Form 10-Q and our audited consolidated financial statements and the accompanying notes included in our 2025 Form 10-K. EXECUTIVE SUMMARY INTRODUCTION Biogen is a global biopharmaceutical company focused on discovering, developing and delivering innovative therapies for people living with serious and complex diseases. We have a broad portfolio of medicines to treat MS, have introduced the first approved treatment for SMA, co-developed treatments to address a defining pathology of Alzheimer’s disease and launched the first approved treatment to target a genetic cause of ALS. We market the first and only drug approved in the U.S., the E.U. and certain international markets for the treatment of FA in adults and adolescents aged 16 years and older. We are focused on advancing our pipeline in neurology, specialized immunology and rare diseases. We support our drug discovery and development efforts through internal research and development programs, external collaborations and acquisitions. Our marketed products include VUMERITY, TYSABRI, TECFIDERA, AVONEX and PLEGRIDY for the treatment of MS; SPINRAZA for the treatment of SMA; SKYCLARYS for the treatment of FA; and QALSODY for the treatment of ALS. We also have collaborations with Eisai on the commercialization of LEQEMBI for the treatment of Alzheimer's disease and Supernus on the commercialization of ZURZUVAE for the treatment of PPD. We have certain business and financial rights with respect to RITUXAN for the treatment of non-Hodgkin's lymphoma, CLL and other conditions; RITUXAN HYCELA for the treatment of non-Hodgkin's lymphoma and CLL; GAZYVA for the treatment of CLL, follicular lymphoma and lupus nephritis; OCREVUS for the treatment of PPMS and RMS; LUNSUMIO for the treatment of relapsed or refractory follicular lymphoma; COLUMVI, a bispecific antibody for the treatment of non-Hodgkin's lymphoma; and have the option to add other potential anti-CD20 therapies, pursuant to our collaboration arrangements with Genentech, a wholly owned member of the Roche Group. We commercialize a portfolio of biosimilars of advanced biologics including: BENEPALI, an etanercept biosimilar referencing ENBREL; IMRALDI, an adalimumab biosimilar referencing HUMIRA; and FLIXABI, an infliximab biosimilar referencing REMICADE. For additional information on our collaboration arrangements, please read Note 18, Collaborative and Other Relationships, to our condensed consolidated financial statements included in this report. We seek to ensure an uninterrupted supply of medicines to patients around the world. To that end, we regularly review our manufacturing capacity, capabilities, processes and facilities. In order to support our future growth and drug development pipeline, we expanded our large molecule production capacity and built a large-scale biologics manufacturing facility in Solothurn, Switzerland. The Solothurn facility is operational and has been approved for the manufacture of LEQEMBI and TYSABRI. We believe that the Solothurn facility will support our anticipated near to mid-term needs for the manufacturing of biologic assets. The plant represents a significant increase in our overall manufacturing capacity. Additionally, we continue to invest to modernize, automate and support the capacity requirements for our pipeline and existing products at our existing manufacturing facilities in RTP, North Carolina. If we are unable to fully utilize our manufacturing facilities, we will incur additional excess capacity charges which would have a negative effect on our financial condition and results of operations. In the longer term, our revenue growth will depend upon the successful clinical development, regulatory approval and launch of new commercial products as well as additional indications for our existing products, our ability to obtain and maintain patents and other rights related to our marketed products, assets originating from our research and development efforts and/or successful execution of external business development opportunities. BUSINESS ENVIRONMENT The biopharmaceutical industry and the markets in which we operate are intensely competitive. Many of our competitors are working to develop or have commercialized products similar to those we market. In addition, the commercialization of certain of our own approved products, products of our collaborators and pipeline product candidates may negatively impact future sales of our existing products. 43 Table of Content Our products and revenue streams continue to face increasing competition in many markets from the introduction of new originator therapies, generics, biosimilars of existing products and products approved under abbreviated regulatory pathways. Some of these products are likely to be sold at substantially lower prices than branded products. Accordingly, the introduction of such products as well as other lower-priced competing products has significantly reduced, and in the future may significantly reduce, both the price that we are able to charge for our products and the volume of products we sell, which can negatively impact our revenue. In addition, in some markets, when a generic or biosimilar version of one of our products is commercialized, it may be automatically substituted for our product and significantly reduce our revenue in a short period of time. Sales of our products depend, to a significant extent, on the availability and extent of adequate coverage, pricing and reimbursement from government health administration authorities, private health insurers and other organizations. When a new pharmaceutical product is approved, the availability of government and private reimbursement for that product may be uncertain, as is the pricing and the amount for which that product will be reimbursed. Drug prices are under significant scrutiny in the markets in which our products are prescribed; for example the IRA has certain provisions related to drug pricing, including the ability for the U.S. government to set prices for certain drugs in Medicare. We expect drug pricing and other healthcare costs will continue to be subject to political and societal pressures on a global basis. As the policy environment remains dynamic, we will continue to monitor how uncertainty with respect to how the U.S. and foreign tariffs and the U.S. and international pricing may impact our business in the future. Additionally, our ability to set the price for our products varies significantly from country to country and, as a result, so can the price or reimbursement of our products. Governments may use a variety of cost-containment measures to control the cost of medicines, including price cuts, mandatory rebates, value-based pricing and reference pricing (i.e., referencing prices in other countries and using those reference prices to set a price). Our failure to obtain or maintain adequate coverage, pricing or reimbursement for our products could have an adverse effect on our business, reputation, revenue and results of operations, could curtail or eliminate our ability to adequately fund research and development programs for the discovery and commercialization of new products and/or could cause a decline or volatility in our stock price. In addition to the impact of competition, pricing actions and other measures being taken worldwide designed to reduce healthcare costs and limit the overall level of government expenditures, our sales and operations could also be affected by other risks of doing business internationally, including the impact of public health epidemics on employees, the global economy and the delivery of healthcare treatments, geopolitical events, tariffs, supply chain disruptions, foreign currency exchange fluctuations, changes in intellectual property legal protections and changes in trade regulations and procedures. For a detailed discussion on our business environment, please read Item 1. Business , in our 2025 Form 10-K. For additional information on our competition and pricing risks that could negatively impact our product sales, please read Item 1A. Risk Factors included in this report. TECFIDERA Multiple TECFIDERA generic entrants are now in North America, Brazil and the E.U. and have deeply discounted prices compared to TECFIDERA. The generic competition for TECFIDERA has significantly reduced our TECFIDERA revenue and we expect that TECFIDERA revenue will continue to decline. In November 2025 the Technical Boards of Appeal of the European Patent Office revoked our EP 2 653 873 patent related to TECFIDERA, after which we stopped enforcing this patent and its national counterparts. For additional information, please read Note 20, Litigation , to our condensed consolidated financial statements included in this report. TYSABRI A biosimilar entrant of TYSABRI was approved in the U.S. and the E.U. in 2023. We expect the future sales of TYSABRI will continue to be adversely affected by the entrance of this biosimilar. BUSINESS UPDATE REGARDING MACROECONOMIC CONDITIONS AND OTHER POTENTIAL DISRUPTIONS Significant portions of our business are conducted in Europe, Asia and other international geographies. Factors such as global health outbreaks, adverse weather events, geopolitical events or conflicts, tariffs, inflation, labor or raw 44 Table of Content