Biogen Inc (BIIB) fair value: what the stock is really worth
We calculate from audited financials what Biogen Inc is really worth. The fair value tells you whether the price is too high or too low, the quality score (0 to 100) how solid the business behind it is. 26 models, 37 quality factors, updated daily.
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Price vs Fair Value
White line = price, green steps = our fair value per fiscal year, dashed = 300-day average. As of Sep 17, 2026.
How to read this chart
60‑month range $113.38 – $388.44 · fair‑value band $166.45 – $309.13 · the $219.07 price screens below the $237.79 fair value. Green steps = our fair value per fiscal year (point-in-time, no hindsight). 2 fiscal years are left out: there the valuation rested on only a fraction of the usual models. Dashed = 300-day average. As of Sep 17, 2026.
Biogen Inc. discovers, develops, manufactures, and delivers therapies in the United States, Europe, Germany, Asia, and internationally.
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Biogen Inc. discovers, develops, manufactures, and delivers therapies in the United States, Europe, Germany, Asia, and internationally. The company provides TECFIDERA, VUMERITY, AVONEX, PLEGRIDY, and TYSABRI for multiple sclerosis (MS); SPINRAZA for spinal muscular atrophy; SKYCLARYS to treat Friedreich's Ataxia; QALSODY for treating amyotrophic lateral sclerosis; FUMADERM to treat plaque psoriasis; BENEPALI, an etanercept biosimilar referencing ENBREL; IMRALDI, an adalimumab biosimilar referencing HUMIRA; FLIXABI, an infliximab biosimilar referencing REMICADE. It offers LEQEMBI for the treatment of Alzheimer's disease; ZURZUVAE for the treatment of postpartum depression; RITUXAN to treat non-Hodgkin's lymphoma, chronic lymphocytic leukemia (CLL), rheumatoid arthritis, two forms of ANCA-associated vasculitis, and pemphigus vulgaris; RITUXAN HYCELA for non-Hodgkin's lymphoma and CLL; GAZYVA to treat CLL and follicular lymphoma; OCREVUS for relapsing MS and primary progressive MS; LUNSUMIO to treat relapsed or refractory follicular lymphoma; glofitamab for aRelapsed or refractory diffuse large B-cell lymphoma; and other anti-CD20 therapies. Biogen Inc. has collaboration and license agreements with Merz Therapeutics; Alkermes Pharma Ireland Limited; Denali Therapeutics Inc.; UCB; Eisai Co., Ltd.; Genentech, Inc.; Neurimmune SubOne AG; Ionis Pharmaceuticals, Inc.; Samsung Bioepis; and Sage Therapeutics, Inc., as well as collaborations with Stoke Therapeutics, Inc. for the development and commercialization of zorevunersen, a disease modifying medicine for the treatment of Dravet syndrome; Dayra Therapeutics, Inc. to develop oral macrocyclic peptides; Vanqua Bio, Inc. for developing Vanqua's preclinical oral C5aR1 antagonist compound; City Therapeutics, Inc. to develop select novel RNAi therapies; and ALTEOGEN Inc. to develop subcutaneous (SC) formulations of biologics utilizing ALT-B4. The company was founded in 1978 and is headquartered in Cambridge, Massachusetts.
Stock analysis
Biogen Inc (BIIB) currently trades at $219.07, while our model-based Fair Value estimate is $237.79, implying the stock looks roughly 7.9% fairly valued today.
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Valuation
Bull case: the DCF Models group reads highest at a median of $269.75 per share, and 12 of the 26 models we run sit above the $219.07 price.
Bear case: the Asset-Based group reads lowest at $82.85, and 14 of the 26 models stay below the price. Evidence for this calculation is medium.
Scenario range: $166.45 (bear) to $309.13 (bull), the price of $219.07 sits inside it. Bear and bull are the same models on cautious and optimistic assumptions, a range, not a price target.
Quality & growth
The Quality Score stands at 63/100 (solid quality), in the Healthcare sector.
Weak Growth: Growth has flattened: the last year, three and five years all grew more slowly than the long-term average.
Biogen Inc reported revenue of $9.8B in FY2025 versus $11.0B in FY2021, a compound −2.8%/yr. Reported net income was $1.3B in FY2025, compounding −4.5%/yr from FY2021.
Key figures
Market cap $32.1B · P/E ratio 23.5 · P/S ratio 3.10 · EPS (TTM) $9.31 · Net margin 13.2% · Return on equity 7.7% · Return on assets (EBIT) 9.3% · Operating margin 22.9%.
Competitive moat
Our AI-assisted moat analysis scores the competitive advantage at 52 out of 100 (low confidence).
What moves the price
The share trades near its 52-week high and 81% above its 52-week low, currently above its 200-day average.
For context, the median of 10 Healthcare peers we cover trades at −1% fair-value upside, at 9%, BIIB screens cheaper than that median.
Fair Value models
Bear $166.45Fair Value $237.79Bull $309.13
Model ⓘEach model values the company its own way (discounted cash flow, earnings, assets, dividends). The fair value above is their evidence-weighted blend, not the output of a single model. Based on fiscal year 2025 figures (about 9 months old). Earnings retained since then ($6.74 per share) are deliberately not added.Bear ⓘBear = the cautious scenario: the same model computed with conservative anchors (lower growth, margins and valuation multiples). Together with Bull it frames a plausible valuation range, not a price target.BaseBull ⓘBull = the optimistic scenario: the same model computed with favourable anchors (higher growth, margins and valuation multiples). Together with Bear it frames a plausible valuation range, not a price target.Evidence ⓘEvidence = how well-backed THIS model's estimate is for this stock (0–100): how complete and reliable its input data are, and how well the model fits the company. The final Fair Value is an evidence-weighted blend, so better-evidenced models count more. Green ≥70, amber 50–69, grey below 50.
Growth Quality ⓘGrowth is valuable only when reinvestment earns attractive returns (Aswath Damodaran): sustainable growth depends on return on capital, reinvestment and efficiency. Basis: total company revenue over the periods shown on the cards (3Y/5Y/all years), not per share, so a merger can show up as a growth jump; per-share earnings growth is in the value-creation card.40/100
Growth has flattened: the last year, three and five years all grew more slowly than the long-term average.
Revenue growth 1 year
+1.4%
Revenue growth 3 years ⓘMeasures the company's TOTAL revenue from reported annual statements: compound average growth per year (CAGR) from the fiscal year 3, 5 or N years back to the most recent comparable fiscal year. Not per share: buybacks do not change this number, and a merger can appear as a growth jump. Per-share growth (which does include buybacks) is in the value-creation card.
−1.2%
Revenue growth 5 years ⓘMeasures the company's TOTAL revenue from reported annual statements: compound average growth per year (CAGR) from the fiscal year 3, 5 or N years back to the most recent comparable fiscal year. Not per share: buybacks do not change this number, and a merger can appear as a growth jump. Per-share growth (which does include buybacks) is in the value-creation card.
−6.1%
Revenue growth 40 years ⓘMeasures the company's TOTAL revenue from reported annual statements: compound average growth per year (CAGR) from the fiscal year 3, 5 or N years back to the most recent comparable fiscal year. Not per share: buybacks do not change this number, and a merger can appear as a growth jump. Per-share growth (which does include buybacks) is in the value-creation card.
+17.6%
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What shareholders gained per year (last 5 years) ⓘWhat the business itself delivers per year: earnings growth per share plus the dividend yield. This is what you get IF the market keeps valuing the stock the same way: it contains no assumption about the market changing its mind. Computed per share, so buybacks count and a merger does not pass as growth. For a company that pays no dividend it is pure earnings growth per share. Period: earnings growth per share as CAGR over the last 5 reported fiscal years (annual statements), plus the current dividend yield. The start value is the median of the three years around the start, so a single crisis year (a pandemic or a write-down) does not distort the rate.
−18.7%
Earnings growth per share plus dividend.
Earnings per share, growth per year−18.7%
Dividend (yield on the price)0.0%
Pace: 5 vs 10 years ⓘTwo data points, not a trend model: earnings growth per share over the last 5 fiscal years against the last 10. Labelled "steady" when both rates are within 3 percentage points of each other, otherwise picking up or flattening. Shown only when ten years of history exist.−19% vs −5%, slowing
Profit margin 2020 to 2025 ⓘOperating margin then vs now, from reported annual statements. A falling margin after a boom year is the classic peak-earnings signal: the growth rate then leans on an inflated base.34% → 19%
Growth Forecast
Price in line with expectations
The price assumes more growth than the company has delivered so far and about what analysts expect.
What the price assumes ⓘThis turns our valuation around: instead of asking what the share is worth, it asks what growth the current price requires. It uses the cash the company keeps after all spending (free cash flow), the same discount rate as our models, five years of growth, then slowing evenly to 2 % a year by year ten. Compared with the analysts' sales forecasts extended to the same five years (at least three analysts, for context only, it does not enter the Fair Value): within 3 percentage points counts as "in line" (amber), below that little optimism (green), above that a lot of optimism (red).
+2.7%
Yearly growth needed for the next five years to justify today's price.
What forecasts expect ⓘAnalysts publish sales forecasts for the next two fiscal years. For the years after that, growth slows evenly to 2 % a year by year ten (2 % is the long-run rate our models use). Projected years are marked as such.
+2.6%
Yearly sales growth analysts expect, extended to five years.
News mood ⓘNews mood, the average tone of recent news (95 articles), rated against how stocks are usually covered. 🚀 Hype = unusually upbeat · 🙂 Positive = above average · 😐 Neutral = typical · 🙁 Negative = below average · 😨 Very negative = unusually downbeat. It reflects the tone of coverage, not our valuation.Hype
Recent news coverage is unusually upbeat, far more positive than stocks are typically covered.
Price, fair value, quality and upside side by side.
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Peer GroupⓘHow this stock ranks against its industry: the green marker is this stock, the band is the typical 25–75% peer range, and the tick is the median.Drug Manufacturers - General · 72 stocks
Beats the industry median on 8/14 measures
A mixed picture versus its industry peers.
Valuation
Quality Score63 · Above median
Fair Value upside+21% · Top 25%
Profitability
Return on equity (TTM)8% · Below median
Return on assets6% · Above median
Net margin (TTM)14% · Above median
Operating margin (TTM)23% · Above median
Growth and dividend
Revenue growth2% · Below median
Balance sheet
Debt / equity0.34× · Above median
Valuation Multiplesvs Drug Manufacturers - General median · lower = cheaper
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Cite: Fair Value Calculator (2026). "Biogen Inc Fair Value". https://www.fairvalue-calculator.com/stock/BIIB
Frequently asked questions
Is Biogen Inc (BIIB) overvalued or undervalued?
As of Sep 17, 2026, our model estimates a fair value of $237.79 versus a price of $219.07, about +9% upside (fairly valued).
What is the fair value of BIIB?
Our model-based fair value for Biogen Inc is $237.79 (as of Sep 17, 2026), built from audited fundamentals. The current price: $219.07.
What is the quality score of BIIB?
Biogen Inc has a Quality Score of 63/100. It measures business quality (profitability, growth, cash flow, balance-sheet strength, investment discipline, share issuance). Market factors such as price momentum and volatility do not enter the number; they are shown separately in the detail view.
What is the price target for Biogen Inc (BIIB)?
Our model-based price target is the fair value of $237.79 (as of Sep 17, 2026) from 26 valuation models. Cautious scenario $166.45, optimistic scenario $309.13. It is a calculation from audited fundamentals, not an analyst target.
What is the Biogen Inc stock forecast for 2026?
Our models put fair value at $237.79, about +9% upside versus a price of $219.07 (fairly valued). Cautious scenario $166.45, optimistic scenario $309.13. The calculation is refreshed regularly with new filings.
What is the revenue of Biogen Inc (BIIB)?
Biogen Inc reported trailing-twelve-month revenue of about $9.9B (latest available figure, as of Sep 17, 2026).
What growth is priced into Biogen Inc (BIIB)?
For today's price to be fair in a discounted-cash-flow model, Biogen Inc would have to grow free cash flow by +2.7 % per year for five years (discount rate 8.1 %, then slowing evenly to 2 % perpetual growth by year ten). Over the last 5 years revenue grew -6.1 % per year. As of Sep 17, 2026.
What discount rate (WACC) does the fair value of BIIB use?
Our models discount Biogen Inc at 8.1 %: a base by market capitalisation (large), damped by beta 0.16, country premium for USA. The same rate applies in all 26 models.
What is a reverse DCF?
A reverse DCF turns the usual calculation around. Instead of deriving a value from assumptions, it takes today's price as given and asks: what free-cash-flow growth would a company have to deliver for exactly this price to be fair? The result is not a forecast but the expectation already priced in. For Biogen Inc that is +2.7 % per year a year over ten years, using the same discount rate (8.1 %) and the same formula as our fair value.
How much growth has Biogen Inc (BIIB) delivered so far?
Over the past 5 years revenue at Biogen Inc grew -6.1 % a year. The price currently implies +2.7 % per year free-cash-flow growth a year. Comparing the two shows how much confidence is in the price: if it demands more than has been delivered, the business has to accelerate for the maths to work.
How fast is the sector of Biogen Inc (BIIB) growing?
The median revenue growth in the sector is +4.3 % a year. That is the yardstick for the growth priced into Biogen Inc (+2.7 % per year a year): it shows whether the expectation is within the usual range or beyond it.
What is the free cash flow yield of Biogen Inc (BIIB)?
The free-cash-flow yield on the price is 6.49 %: that much free cash flow Biogen Inc produces per unit of market value. When it exceeds the discount rate of our models (8.1 %), the business already earns more than its cost of capital demands, and the price needs little additional growth.
What is the intrinsic value of Biogen Inc (BIIB)?
Intrinsic value and fair value mean the same thing: what the business is worth on its numbers, independent of the share price. For Biogen Inc it is $237.79 per share (as of Sep 17, 2026), against a price of $219.07. It is the blended result of 26 valuation models (cash flow, earnings, asset, dividend).
Is Biogen Inc stock overvalued or undervalued in 2026?
As of Sep 17, 2026, BIIB trades below its calculated fair value: price $219.07, fair value $237.79, a gap of about +9% (fairly valued). The calculation is refreshed with each new quarterly report, so the verdict can change during the year.
Is fair value the same as the market price of BIIB?
No. The price is what the market pays today ($219.07); the fair value is what the company's own numbers justify ($237.79). For Biogen Inc the two are $18.72 per share apart. That gap is exactly why we show both numbers side by side.
How much is Biogen Inc worth?
The market values Biogen Inc at about $32.1B (market capitalisation, as of Sep 17, 2026). Per share that is $219.07; our models calculate a fair value of $237.79 per share.
What do the bullish and bearish scenarios say about BIIB?
Our models span a range for Biogen Inc: cautious scenario $166.45, base $237.79, optimistic $309.13 per share (as of Sep 17, 2026, price $219.07). The range comes from different growth and margin assumptions, not from analyst opinions.
What is the P/E ratio of BIIB?
Biogen Inc trades at a price-to-earnings ratio of 23.5 (as of Sep 17, 2026). A P/E on its own says little: it compares the price with ONE year of profit, while our fair value of $237.79 is built from several models across several years. Other multiples: PEG 4.2, P/B 1.7, P/S 3.1, EV/EBITDA 9.6.
What is the PEG ratio of BIIB?
The PEG ratio of Biogen Inc is 4.16 (P/E divided by earnings growth, as of Sep 17, 2026). That is above 1, so the growth is already paid for in the price.
How solid is the balance sheet of Biogen Inc (BIIB)?
Balance-sheet figures for Biogen Inc (as of Sep 17, 2026): return on equity 7.7%, debt of 0.34 per unit of equity. They feed the Quality Score of 63/100, which measures business quality independently of the share price.
How far is BIIB from its 52-week high?
Biogen Inc trades at $219.07, about 6% below its 52-week high of $205.97 and 81% above the low of $121.05 (as of Sep 17, 2026). Distance from the high says nothing about value: that is what the fair value of $237.79 is for.
Which stocks are comparable to Biogen Inc?
From the same area (Healthcare) we also value Eli Lilly and Company, Johnson & Johnson,, AbbVie Inc, Roche Holding, among others. Each of them has its own fair-value calculation on this site using the same models, so the comparison is like for like.
Is Biogen Inc stock attractive at the current price?
The data as of Sep 17, 2026: price $219.07, calculated fair value $237.79 (+9%), Quality Score 63/100, from 26 models. Whether that fits your horizon and risk tolerance is your call. We provide the calculation, not investment advice.
How is the fair value of BIIB calculated?
We run Biogen Inc through 26 models from four families: discounted cash flow, earnings models, asset and balance-sheet models, and dividend models. Every model gets the same audited fundamentals; the result is the weighted average of $237.79, with the spread shown as a cautious and an optimistic scenario.
Is it still worth investing in stocks now?
The global stock market currently sits 16.1 % above its aggregate fair value. Biogen Inc currently trades 9 % below its own fair value, and the market average says nothing about that. An expensive market is no reason to stay out and no reason to buy everything at once: keep a broad savings plan running, buy single stocks only with money you can do without, and hold part of your money liquid while the market is high. The full picture including sectors is on is it worth investing now.
What is the share price of Biogen Inc (BIIB)?
The closing price on Sep 21, 2026 was $219.07. Our model-based fair value is $237.79, about +9% upside (fairly valued). We carry closing prices from our data provider, not a live tick.
What should I pay attention to with Biogen Inc right now?
The price sits close to our fair value, market and models broadly agree here, little valuation tension. A fairly wide model range ($166.45 to $309.13) leaves room in how you read the outcome.
Where does the earnings growth of Biogen Inc (BIIB) come from?
Earnings per share at Biogen Inc grew −5.0 % a year from 2014 to 2025. Broken into its drivers: revenue per share +4.1 %, EBIT margin −7.4 %, tax rate +1.9 %, residual (interest, one-offs) −3.4 %. The four rates multiply to the earnings growth rate, they do not add up. Start and end are three-year averages so a single exceptional year does not distort the result.
Key figures of Biogen Inc
How large is the market capitalisation of Biogen Inc (BIIB)?
The market capitalisation of Biogen Inc is $32.1B. The stock-market value of the whole company: share price times number of shares. It is what the market asks for the entire business today.
What is the P/S ratio of Biogen Inc (BIIB)?
The price-to-sales ratio of Biogen Inc is 3.10 (P/E × margin). Price to sales: market value relative to yearly revenue. Useful when profit is thin or distorted.
What are the earnings per share of Biogen Inc (BIIB)?
Earnings per share at Biogen Inc are $9.31 (price ÷ EPS = P/E 23.5). Earnings per share over the last twelve months: total profit spread across every single share.
What is the net margin of Biogen Inc (BIIB)?
The net margin of Biogen Inc is 13.2% (fiscal year 2025). How much of every unit of revenue ends up as profit. 10% means 10 cents of profit per dollar of sales.
What is the return on equity of Biogen Inc (BIIB)?
The return on equity (ROE) of Biogen Inc is 7.7% (last twelve months). Profit relative to shareholders' equity, how efficiently the company works with its owners' money.
What is the EBIT return on assets of Biogen Inc (BIIB)?
On an EBIT basis the return on assets of Biogen Inc is 9.3% (avg 5y). Operating profit (EBIT) relative to everything the company owns, as a multi-year average. It describes the business model rather than one good or bad year.
What is the operating margin of Biogen Inc (BIIB)?
The operating margin of Biogen Inc is 22.9% (last twelve months). Profit from the core business (before interest and taxes) relative to revenue.
How fast is revenue growing at Biogen Inc (BIIB)?
Revenue at Biogen Inc is growing +1.9% versus a year earlier (3y avg −1.2%). How much revenue grew versus a year earlier (YoY). The 3-year average next to it puts the single year in context.
How fast are earnings growing at Biogen Inc (BIIB)?
Earnings per share at Biogen Inc are growing +31.1% versus a year earlier. How much earnings per share grew versus a year earlier.
How much net debt does Biogen Inc (BIIB) carry?
The net debt of Biogen Inc is $3.9B (fiscal year 2025, ≈ 1.9 yrs of FCF). Debt minus cash on hand. The note shows how many years of free cash flow could in theory pay it off.
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Some data
Sep 17, 2026