Biogen Inc (BIIB) stock analysis
Biogen Inc (BIIB) clears 3 of this site's 8 mechanical value filters, 4 of 8 Buffett-style checks and 2 of 5 Lynch-style checks. At $253.84 it trades 14.9% below this site's neutral DCF value (a margin of safety of +14.9%). Its earnings quality rates Strong and it returns −0.8% to shareholders net of dilution. Figures are as of October 23, 2026, from SEC filings and market data refreshed weekly; this is educational analysis, not investment advice.
Data as of October 23, 2026. Refreshed weekly from SEC filings and market data.
What does Biogen do?
Biogen develops and sells medicines for neurological diseases such as multiple sclerosis and Alzheimer's, plus rare diseases, and earns royalties from partners.
Brands and businesses it owns
- Tysabri
- Tecfidera
- Spinraza
- Leqembi (with Eisai)
- Skyclarys
What stands out about Biogen?
- The share price implies 4.0% yearly growth. At $253.84, BIIB's free cash flow of $17.47 per share would have to grow 4.0% a year, fading to 2.5% by year 10, for this site's DCF (10% discount rate) to match the price. This site's baseline starts at 8%, so the price asks for less growth than the baseline. Change the assumptions.
- Misses 3 of the 8 value filters. It fails Trailing P/E < 25 (44.21), PEG Ratio < 1.5 (7.83) and EPS Growth YoY > -5% (-84.8%); the other 3 pass and 2 were not evaluated. See every filter.
- The margin of safety is falling. It went from +24% on Oct 7 to +15% on Oct 23 across 5 weekly readings. See the trend.
- Close to its 52-week high. At $253.84, BIIB is within 0.0% of its high of $253.09, 78.4% above its low of $142.26. See the range.
- Owners are being diluted. Its net shareholder yield is −0.8%: more stock is issued than is bought back or paid out. See Shareholder Yield Leaders.
How has Biogen's share price moved?
The interactive price chart needs JavaScript.
Is Biogen undervalued? The value diligence check
Every value-investing signal this site computes for this stock, gathered in one place: the same real numbers from the tools below, not a new score.
- Margin of safety (DCF) +14.9%
- P/E vs. its own history 44.2x · at/above its priciest point Real range: 13.3x–32.5x over 5 years (net income per diluted share from each fiscal year's 10-K, paired with the real closing price at that fiscal year-end).
- Wall St. analyst rating Buy · 3.88/5 43 analysts this month: 10 strong buy, 19 buy, 13 hold, 1 sell, 0 strong sell (Finnhub). Down from 3.91 last month.
- Earnings quality (is the profit real?) Strong · all 5 checks clean Beneish M-score −2.68 · accruals −3.2% of assets · 162% of profit arrived as cash · stock comp 2.9% of revenue · share count +0.5% a year. From the latest 10-K (year to Dec 2025) - see the Earnings Quality Screener for how each check is scored.
- Shareholder yield (cash back to owners) −0.8% net Latest fiscal year (2025): dividends 0.0% + buybacks 0.0% − stock comp 0.8%, as a share of today's market cap. Stock comp outruns what comes back in cash. Over 14 years its split-adjusted share count fell 40%. See Shareholder Yield Leaders.
- Capital needed to grow (See's test) Profit did not grow in 10 years Operating profit $5.5B → $1.8B, capital needed $12B → $23B, 2016–2025 (3-year averages); return on capital now 8% before tax. Buffett's See's Candies needed $0.42 per $1 of new profit, FlightSafety $3.20, a typical grower about $5. See Capital-Light Compounders.
- PEG (growth at a reasonable price) 7.83 · Well above fair P/E 44.2× ÷ 5.7% a year of growth behind it. 427th lowest of 447 stocks with a usable PEG. Lynch's fair value is a PEG of 1; a very high PEG usually means almost no growth, a very low one a profit spike. See PEG Ratio Ranking.
- Compounder lenses (4) 1 of 4 · misses capital-light, cash back, price Capital-light growth: not cleared (profit grew 0.3×, under 2×); Profit is real: cleared; Cash to owners: not cleared (−0.8% a year net); Fair price (PEG): not cleared (PEG 7.83, over 1.5). See Compounders at a Fair Price, which also lets you move the PEG bar.
- Value trap check Flagged (3/6 filters failed)
- Munger's Inversion Check 1 flag
- Standing vs. sector peers 2 of 6 measures above the median Compared with the 14 other pharma & biotech stocks this site tracks: 2 in the top third, 3 in the bottom third.
How does Biogen compare with its peers?
2 of 6 measures sit above the median of the 14 other pharma & biotech stocks tracked here, 2 in the top third and 3 in the bottom third.
- P/E ratiolower is cheaper · peer median 35.0× 44.2× ✕9th of 12
- Free-cash-flow yieldhigher is cheaper · peer median 4.5% 6.9% ✓5th of 15
- Return on equityhigher is better · peer median 23% 5% ✕12th of 15
- Net marginhigher is better · peer median 16.2% 8.3% –10th of 15
- Revenue growthhigher is better, year on year · peer median 5.5% 0.3% ✕13th of 15
- Debt / equitylower is safer · peer median 0.94 0.43 ✓5th of 15
Peers are the stocks this site tracks in the same sector group, not every listed competitor. The bar runs from the weakest peer (left) to the strongest (right); the tick is the middle. Measures that don't apply to a sector (cash-flow yield for banks, debt for financials) are left out.
What would Buffett & Lynch say?
Buffett's checklist is built around durable, profitable businesses bought at sensible prices, and BIIB doesn't clear enough of it yet. In its favor: BIIB and has kept that profitability up over five years, not just this year, carries a conservative amount of debt relative to equity, is trading below what a conservative discounted-cash-flow estimate says it's worth - his own "price is what you pay, value is what you get" test, not a fixed multiple ceiling, and trades at a reasonable multiple of owner earnings, his own term for the real cash a business could pay out. Where it comes up short: BIIB isn't clearing the return-on-equity bar he'd want to see right now, runs thinner pretax margins than he'd like to see, hasn't grown earnings per share fast enough over five years to impress him, and doesn't cover its interest expense as comfortably as he'd want.
- ROE (TTM) > 11% ✕
- ROE (5yr avg) > 11% ✓
- Debt/Equity < 0.5 ✓
- Pretax margin > 15% ✕
- EPS growth (5yr) > 7% ✕
- Interest coverage > 5x ✕
- Trading below intrinsic value (DCF) ✓
- Price vs. owner earnings < 25x ✓
Lynch looked for growth stories that weren't overpriced for that growth, and BIIB falls short of his bar. In its favor: BIIB isn't over-leveraged for a company of its type, and converts earnings into real cash at a reasonable price. Where it comes up short: BIIB doesn't pay much of a dividend, which is the main reason to own a slow grower in the first place, isn't even growing at the modest pace he'd expect from a slow grower, and is priced too rich for how little growth is actually left in the business.
- Dividend yield > 2.5% ✕
- EPS growth 0%-10% ✕
- Debt/Equity < 0.6 ✓
- P/E < 20 ✕
- Price/FCF < 25 ✓
Quantitative approximations of each investor's documented approach, not endorsed by either investor or their estates - commentary, not this site's actual ranking criteria. Buffett never published a numeric checklist: only 2 of his 8 checks here trace to his own documented concepts ("owner earnings," from his 1986 shareholder letter, and "price is what you pay, value is what you get," his case against fixed P/E/P/B ceilings) - the other 6 (ROE, debt, margins, growth, interest coverage) use commonly-cited thresholds that are not numbers he himself published. The 8 hard filters below (plus the Munger check and Graham margin of safety) are this site's real, mechanical screen and are computed completely independently of the checklists above.
Berkshire Hathaway's own filing
Which of the 8 value filters does Biogen pass?
- Market Cap > $25B $36.9B
- Trailing P/E < 25 44.21
- PEG Ratio < 1.5 7.83
- Price/Book < 8 1.96
- Price/Sales < 7 3.68
- EPS Growth YoY > -5% -84.8%
- vs 50-day MA (±12%) Not evaluated †
- vs 200-day MA (±12%) Not evaluated †
What is Biogen's margin of safety?
+24% on 2026-10-07 → +15% on 2026-10-23 (5 weekly readings).
Where is Biogen in its 52-week range?
What is the short interest in Biogen?
5,965,892 shares short as of 2026-09-30 (FINRA settlement date). Reported twice a month, so this only changes roughly every two weeks, not daily.
What could go wrong with Biogen? Munger's inversion check
"Invert, always invert." Instead of reasons to buy, these are reasons to hesitate, not a verdict, and not everything worth knowing about a business.
- Margin of safety, even in the bull case +50%
- Short interest under 5% of float 4.1%
- Passes most of the 6 fundamental filters 3/6 passed
- Price run-up backed by value, not just momentum +78% off 52wk low
- Debt/equity stable since 2016 0.54 → 0.34
Doesn't cover circle of competence, management quality, or accounting concerns: those need judgment, not data.
How much have Biogen shareholders gained per year?
Earnings growth per share plus dividend.
An earnings-based proxy, not a stock-price total return - it doesn't capture multiple expansion/contraction or reinvested dividends. EPS from BIIB's own 10-K filings; dividend yield is the current trailing yield on today's price, from the same weekly fetch as the rest of this site.
What do Biogen's 10-year financials show?
From BIIB's own 10-K filings (SEC EDGAR): up to the last 10 fiscal years. Press any year's bars for the exact figures.
Frequently asked questions about Biogen
What kind of company is Biogen?
Biogen develops and sells medicines for neurological diseases such as multiple sclerosis and Alzheimer's, plus rare diseases, and earns royalties from partners. Brands and businesses it owns include Tysabri, Tecfidera, Spinraza, Leqembi (with Eisai) and Skyclarys. This site groups it with Biotechnology stocks.
Is Biogen trading above or below its DCF value?
At $253.84, BIIB trades 14.9% below this site's neutral DCF value of $298.37 per share, a margin of safety of +14.9%. That DCF projects free cash flow for 10 years, with growth starting at 8% and fading to 2.5%, discounted at 10%; it is one set of assumptions, not a forecast. Test your own in the Intrinsic Value Calculator.
How many of this site's 8 value filters does Biogen pass?
BIIB passes 3 of 8. It passes Market Cap > $25B ($36.9B), Price/Book < 8 (1.96) and Price/Sales < 7 (3.68). It misses Trailing P/E < 25 (44.21), PEG Ratio < 1.5 (7.83) and EPS Growth YoY > -5% (-84.8%). vs 50-day MA (±12%) and vs 200-day MA (±12%) were not evaluated, because the moving-average checks only run on stocks that clear the fundamentals first. The 8-filter list shows every stock that passes all of them.
How fast has Biogen grown its revenue and profit?
From fiscal 2016 to fiscal 2025, BIIB's revenue fell from $11.4 billion to $9.9 billion, 1.6% a year. Net income went from $3.7 billion to $1.3 billion, and its net profit margin from 32.3% to 13.1%. Earnings per share went from $16.92 to $8.79 on today's share count, -7.0% a year. In fiscal 2025 it produced $2.1 billion of free cash flow (cash from operations minus capital spending), 20.7% of its revenue. All figures are from BIIB's own 10-K filings (SEC EDGAR) and are shown year by year in the 10-Year Financials section of the card above.
Where is Biogen trading compared with its 52-week range?
At $253.84, BIIB is at its 52-week high of $253.09, 77.9% above its 52-week low of $142.26.
When does Biogen report earnings next?
Biogen's next earnings report is expected on October 28, 2026 before the market opens, with analysts expecting earnings of $2.04 per share. Dates come from the Finnhub earnings calendar and can move. In its last 4 quarters it beat the estimate 4 times, by an average of +22.1%.
Where do these numbers come from?
- Financial statements: Biogen's 10-K annual report for the year ended Dec 31, 2025, filed Feb 6, 2026 (filing index). Every earlier year in the 10-year financials comes from the company's older 10-K filings, all listed on SEC EDGAR.
- Prices and market data: quotes, P/E and analyst ratings from Finnhub; daily price history and the 52-week range from Twelve Data, both refreshed weekly. Short interest comes from FINRA, reported twice a month.
- How to check a figure: click any number in the card above to see its exact source, and read the Editorial Standards for every rule behind the checks.
About this Biogen Inc analysis
This page shows every value-investing check the site runs on Biogen Inc (BIIB) in one place: the 8 mechanical filters, the Buffett and Lynch checklists, a margin of safety from a disclosed DCF, earnings quality, shareholder yield and how it ranks against its sector peers. The numbers come from SEC filings and public market data, refreshed weekly, and the same rules apply to every stock on the stock list. See Editorial Standards for the sources and the rules, or run your own filters in the stock screener.