At a glance
Biogen Inc is worth $36.81B, about 28 times its fiscal 2025 earnings. Revenue grew 2.2% to $9.89B in fiscal 2025, with 13.1% kept as profit; over 5 years it has grown 6.0% a year. It pays no dividend; it spent $2.55B buying back its shares over FY2021–FY2025. The stock returned +61.4% over the past year with dividends reinvested and −1.8% a year over five years, against +11.5% and +11.7% for the S&P 500. At its worst it fell 21.2% in the 2020 crash (S&P 500: 33.7%) and 23.2% in the 2022 bear market (S&P 500: 24.5%), and was back at its earlier high 1 month and 5 months after the lows.
The business in plain English
Biogen is a global drug company that sells medicines for serious diseases of the brain and nervous system, plus some rare diseases. Its largest business is multiple sclerosis (MS), in which the immune system damages nerves. Its MS drugs are TYSABRI, VUMERITY, TECFIDERA, AVONEX and PLEGRIDY. It also sells SPINRAZA, the first approved treatment for spinal muscular atrophy (SMA), a genetic disease that weakens muscles; SKYCLARYS for Friedreich's ataxia; and QALSODY, the first approved drug to target a genetic cause of ALS.
Partnerships add more revenue. Biogen collects royalties on OCREVUS, an MS drug from Genentech, part of the Roche Group, and holds rights in Genentech blood-cancer drugs such as RITUXAN and GAZYVA. It works with Eisai on the Alzheimer's drug LEQEMBI and with Supernus on ZURZUVAE for postpartum depression. It also sells biosimilars, close copies of complex drugs made from living cells, such as BENEPALI (a version of ENBREL), and makes drugs for other companies under contract.
Revenue was $9.89 billion in 2025. The largest sources were TYSABRI at 16.8%, SPINRAZA at 15.6% and the OCREVUS royalty at 14.3%. VUMERITY, AVONEX and TECFIDERA each added between 6.9% and 7.6%, and contract manufacturing 6.9%. Sales depend on insurers and governments agreeing to cover its drugs. Its research pipeline focuses on neurology, specialized immunology and rare diseases.
Price history
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BIIB +61.4% over the year to Nov 2, 2026, total return with dividends reinvested.
How it makes money
By product or service
| TYSABRI | $1.67B | 16.8% |
| SPINRAZA | $1.55B | 15.6% |
| Royalty revenue on sales of OCREVUS | $1.41B | 14.3% |
| VUMERITY | $746.8M | 7.6% |
| Contract manufacturing, royalty and other revenue | $732.9M | 7.4% |
| AVONEX | $695.5M | 7% |
| TECFIDERA | $679.7M | 6.9% |
| Contract manufacturing revenue | $679.4M | 6.9% |
| Completed technology for SKYCLARYS (U.S.) | $520.5M | 5.3% |
| BENEPALI | $453.2M | 4.6% |
| PLEGRIDY | $250.1M | 2.5% |
| Other | $197.2M | 2% |
| ZURZUVAE | $195.1M | 2% |
| IMRALDI | $190.2M | 1.9% |
Latest results
- In Q3 FY2026 (ended Sep 30, 2026), revenue was $2.80B, up 10.6% from a year earlier, and net income was $-20.6M (-104.4%).
- For fiscal 2025, revenue was $9.89B (+2.2% year over year; -6.0% a year from FY2020 to FY2025) with a 13.1% net margin.
Financial health check
| Revenue growth a year (FY2020–FY2025) | -6.0% weak |
|---|---|
| Free cash flow margin | 20.7% good |
| Return on equity (FY2025) | 7.1% weak |
| Return on assets (FY2025) | 4.4% watch |
| Net cash (cash minus debt) | $-5.99B weak |
| Fiscal year | Revenue | Net income | Free cash flow |
|---|---|---|---|
| FY2020 | $13.44B | $4.00B | $3.81B |
| FY2021 | $10.98B | $1.56B | $3.38B |
| FY2022 | $10.17B | $3.05B | $1.14B |
| FY2023 | $9.84B | $1.16B | $1.27B |
| FY2024 | $9.68B | $1.63B | $2.72B |
| FY2025 | $9.89B | $1.29B | $2.05B |
Valuation snapshot
| Market value | $36.81B |
|---|---|
| P/E ratio | 28.3 |
| Dividend yield | None |
Rank among 1514 US companies
Market value at each year end
Biogen’s market value went from $61.70B at the end of 2016 to $36.81B on Nov 2, 2026, down 40%; since the end of 2025 it is up 43%.
Show as a table
| Year end | Market value | Change |
|---|---|---|
| Nov 2, 2026 | $36.81B | +42.6% |
| 2025 | $25.82B | +15.9% |
| 2024 | $22.28B | -40.6% |
| 2023 | $37.50B | -6.0% |
| 2022 | $39.88B | +13.1% |
| 2021 | $35.24B | -6.5% |
| 2020 | $37.68B | -29.6% |
| 2019 | $53.54B | -11.7% |
| 2018 | $60.63B | -10.0% |
| 2017 | $67.37B | +9.2% |
| 2016 | $61.70B |
Price behavior
| YTD | 1 yr | 3 yr | 5 yr | 10 yr | |
|---|---|---|---|---|---|
| BIIB price data to Nov 2, 2026 | +41.5% | +61.4% | +1.0% | -1.8% | -1.1% |
Show as a table
| Year | Price data |
|---|---|
| 2026 (to date) | +41.5% |
| 2025 | +15.1% |
| 2024 | -40.9% |
| 2023 | -6.5% |
| 2022 | +15.4% |
| 2021 | -2.0% |
| 2020 | -17.5% |
| 2019 | -1.4% |
| 2018 | -5.5% |
| 2017 | +12.3% |
| 2016 | -7.4% |
| 2015 | -9.8% |
| 2014 | +21.4% |
| 2013 | +91.0% |
| 2012 | +33.0% |
| 2011 | +64.1% |
| 2010 | +25.3% |
| 2009 | +12.3% |
| 2008 | -16.3% |
| 2007 | +15.7% |
| 2006 | +8.6% |
| 2005 | -32.0% |
| 2004 | +81.5% |
| 2003 | +10.6% |
| 2002 | -51.9% |
| 2001 | +9.1% |
| 2000 | +92.9% |
| 1999 | +318.1% |
| 1998 | +36.7% |
| 1997 | +44.7% |
| 2008 financial crisis stocks fell Oct 9, 2007 – Mar 9, 2009 | Lost 34.8% over that stretch · deepest drop along the way 52.7%, back to its old high 28.4 months after the low |
|---|---|
| 2020 COVID crash stocks fell Feb 19, 2020 – Mar 23, 2020 | Lost 21.1% over that stretch · deepest drop along the way 21.2%, back to its old high 1.2 months after the low |
| 2022 bear market stocks fell Jan 3, 2022 – Oct 12, 2022 | Gained 3.9% over that stretch · deepest drop along the way 23.2%, back to its old high 4.7 months after the low |
Insider activity
Form 4 filings from 2025-11-03 to 2026-11-03 (25 read): 1 open-market purchases ($585.11) and 2 sales ($240K), 2 of them under pre-arranged 10b5-1 trading plans.
| Date | Insider | Type | Value |
|---|---|---|---|
| Aug 3, 2026 | Lloyd Minor Director | sell (plan) | $121K |
| Aug 4, 2026 | Lloyd Minor Director | sell (plan) | $119K |
| Feb 12, 2026 | Nicole Murphy Head of Pharm Ops and Tech | buy | $585.00 |
Who owns it
Large shareholders (13G filings)
| FMR LLC | 12.4% | Jun 30, 2026 |
| PRIMECAP MANAGEMENT CO/CA/ | 10.2% | Sep 30, 2025 |
| BlackRock, Inc. | 8.5% | Mar 31, 2025 |
| Vanguard Capital Management | 7.48% | Mar 31, 2026 |
| STATE STREET CORPORATION | 5% | Sep 30, 2025 |
ETFs with the most weight in BIIB
| PBE Invesco Biotechnology & Genome ETF | 4.71% |
| IBRN iShares Neuroscience and Healthcare ETF | 4.21% |
| FTXH First Trust Nasdaq Pharmaceuticals ETF | 3.5% |
| BBH VanEck Biotech ETF | 3.29% |
| MNTL Tema Neuroscience and Mental Health ETF | 3.22% |
| FBT First Trust NYSE Arca Biotechnology Index Fund | 3% |
| MEDX Horizon Kinetics Medical ETF | 2.47% |
| XBI SPDR S&P Biotech ETF | 2.41% |
What could go wrong
- A handful of products drive revenue. TYSABRI (16.8% of 2025 revenue), SPINRAZA (15.6%) and the OCREVUS royalty (14.3%) are the biggest sources. Rival drugs, safety problems or pricing pressure on any one could hurt results.
- LEQEMBI's launch leans on partner Eisai. The Alzheimer's drug is early in its launch. Eisai handles reimbursement, use can require registry enrollment and imaging, and Biogen filed for arbitration with Eisai in June 2025 over sales plans in Europe.
- Generic, biosimilar and new rival drugs. Biogen sells into increasingly competitive markets. Generic and biosimilar versions of its products, and new treatments with better insurance coverage, can take patients and push prices down.
- Pipeline bets may not pay off. Few research programs become approved products. In 2025 Biogen paid $165 million upfront to co-develop Stoke's zorevunersen, an epilepsy drug that entered late-stage (Phase 3) testing in August 2025.
- Government limits on drug prices. Price negotiation under the Inflation Reduction Act, most-favored-nation pricing (matching lower prices paid abroad) and executive orders could reduce what Biogen can charge for its medicines in the US.
- Debt far exceeds cash. As of September 30, 2026, Biogen had $7.29 billion of debt and $1.30 billion of cash and investments. Biogen warns this debt could limit its flexibility to respond to business changes.
Recent events
- Quarterly results released
- Quarterly results released
- Quarterly results released
- Shareholder vote results
- Major agreement signed; Acquisition or sale of assets completed; New debt or financial obligation; Investor presentation or announcement
- Quarterly results released
- Quarterly results released
- Major agreement signed; Other company announcement
- Executive or board change
- Executive or board change; Other company announcement
For income and retirement investors
Biogen pays no dividend. It paid none from 2021 through 2025, so the stock provides no regular income; any cash would have to come from selling shares. The company has returned money through buybacks (purchases of its own shares) instead, spending $2.55 billion over those five years. But it repurchased no stock in 2023 or 2024, and shares outstanding rose 0.6% from February 2, 2022 to October 26, 2026.
In past downturns, the stock fell 52.7% during the 2008 financial crisis and took until April 2011 to recover. It dropped 21.2% in the 2020 COVID crash but recovered in just over a month. In 2022 it fell 23.2% by May, yet over the market's slide from January to October it gained 3.9%. Its deepest drop in the three years to October 28, 2026 was 57.6%. Single stocks carry more risk than diversified funds, because one company's setback can sink the whole investment.
Questions investors ask
Does Biogen pay a dividend?
No. Biogen paid no dividends in fiscal years 2021 through 2025, and the stock had no dividend yield as of October 28, 2026. The company has used share buybacks instead, spending $2.55 billion on its own stock over those five years. It bought back none in 2023 or 2024, and the share count rose 0.6% from February 2, 2022 to October 26, 2026. For an income investor, any cash from this stock would have to come from selling shares.
How does Biogen make money?
Biogen earns money by selling medicines for neurological and rare diseases and by collecting royalties from partners. Of its $9.89 billion in 2025 revenue, the multiple sclerosis (MS) drug TYSABRI brought in 16.8%, the spinal muscular atrophy drug SPINRAZA 15.6% and royalties on Genentech's MS drug OCREVUS 14.3%. The MS drugs VUMERITY, AVONEX and TECFIDERA added between 6.9% and 7.6% each. Other revenue comes from contract manufacturing and biosimilars such as BENEPALI, and Biogen works with Eisai on the Alzheimer's drug LEQEMBI.
Is Biogen's revenue growing?
Modestly, after several years of decline. Revenue rose 2.2% to $9.89 billion in 2025, but that was down from $13.44 billion in 2020, a fall of about 6% a year over five years. Net income fell 20.8% to $1.29 billion in 2025. In the quarter ended September 30, 2026, revenue grew 10.6% from a year earlier to $2.80 billion, but Biogen posted a net loss of $20.6 million.
How has Biogen stock performed over the long term?
Weakly over the long run, despite strong gains in the latest 12 months. As of October 28, 2026, the share price was up 63.6% over one year and 38.7% year to date. Over 10 years, though, it was down 14% in total, or about 1.5% a year, and over five years it lost about 1.6% a year. The stock fell 40.9% in 2024 alone. Over roughly 30 years of trading, its deepest decline was 76.2%.
What is Biogen's P/E ratio?
Biogen's price-to-earnings (P/E) ratio was 27.8 as of October 28, 2026, based on 2025 diluted earnings of $8.79 per share. The P/E divides the share price by a year's earnings per share. Biogen's earnings swing widely, which makes any single year's P/E less reliable: diluted earnings per share were $24.80 in 2020, $20.87 in 2022 and $7.97 in 2023. The company's market value was about $36.1 billion on October 28, 2026.