NASDAQ: BIIB · General Drug Manufacturers
Biogen (BIIB) fair value: undervalued or overvalued?
As of 29 Sep 2026, Faircurve's model values Biogen (BIIB) at $236.19 a share. The stock last closed at $219.88, which puts the model's fair value 7.4% above the price. On the model's bands that reads as Fairly valued.
Revalued . Price is the close of 2 Oct 2026. Biogen Inc.
Faircurve Insights · 29 Sep 2026
Biogen Inc. is a leading biotechnology firm dedicated to the discovery, development, production, and distribution of treatments for complex neurological and neurodegenerative conditions.
Faircurve's model found a fair value of $236.19 a share on 29 Sep 2026, the midpoint of 2,000 simulations. The previous run on 26 Sep 2026 gave $235.33, a move of +0.4%. The model's calibrated range over 63 trading days is $203.53 to $261.05; this type of range held the price 60% of the time at this horizon, and the evidence grade is Medium.
The overall quality score is 49 out of 100 against comparable companies, with profitability at 17 and earnings quality at 100. The model compares it with Bristol-Myers Squibb Company, Pfizer Inc., Gilead Sciences, Inc., Amgen Inc., Merck & Co., Inc., AbbVie Inc., and Johnson & Johnson. The stock moved around its last 8 earnings reports with a median size of 3.7%.
Written from the figures on this page for the 29 Sep 2026 valuation and checked by rule before publishing: every number is one printed here, no forecast, no instruction. The price, the gap and the verdict are the page's own and change daily. Not a recommendation.
What price range does the model give BIIB?
The calibrated range for BIIB over 63 trading days is $200.84 to $257.60. It sits around the last close, and its width comes from the volatility that BIIB's own options imply (35% a year), calibrated weekly against realised prices (n = 3,330 past valuations, refreshed 26 Sep 2026). Ranges built this way held the price 60% of the time at this horizon. The fair value is the model's opinion and rides beside the range. It is not the centre of it.
The model's own simulated range, from the 20th to the 80th percentile of its runs, is $179.02 to $305.65. In 54% of the simulations the fair value came out above the price the model ran on.
How does BIIB score on business quality?
Biogen's overall quality score is 49 out of 100. Each factor below is a score against comparable companies, not a percentile of the metric beside it.
| Factor | Score (0 to 100) | Headline measure | Peer median |
|---|---|---|---|
| ProfitabilityReturn on invested capital against the peer group, with a bonus for an improving trend. | 17 | 4.8%ROIC | 20.1% |
| Earnings qualityHow much of reported profit is cash: free cash flow to net income, and the accrual ratio (the share of earnings that is not cash). | 100 | 3.55xFCF / net income | 0.98x |
| Growth qualityTrailing revenue growth, forward growth from consensus, and the direction of analyst estimate revisions. | 46 | 1.4%Revenue growth, trailing | 6.0% |
| Capital disciplineReinvestment efficiency (capital spending per unit of revenue) and net buybacks. | 66 | 0.0%Net buybacks / market value | 1.3% |
| Balance sheetNet debt to EBITDA and interest coverage. | 18 | 4.23xNet debt / EBITDA | 0.60x |
| StabilityDownside volatility of the EBITDA margin over the last five years. | 64 | 3.3 ptsEBITDA margin downside volatility, 5y | 6.6 pts |
How does BIIB compare with similar companies?
The companies in general drug manufacturers closest to Biogen in market value, each on the same model and the same date.
| Company | Last close | Model fair value | Gap | Model verdict |
|---|---|---|---|---|
| BMY Bristol-Myers Squibb Company | $61.15 | $71.30 | +16.6% | Undervalued |
| PFE Pfizer Inc. | $27.80 | $31.76 | +14.2% | Fairly valued |
| GILD Gilead Sciences, Inc. | $144.74 | $142.59 | -1.5% | Fairly valued |
| AMGN Amgen Inc. | $403.04 | $448.86 | +11.4% | Fairly valued |
| OGN Organon & Co. | $13.72 | $13.80 | +0.6% | Low evidence grade |
| MRK Merck & Co., Inc. | $144.30 | $125.73 | -12.9% | Fairly valued |
| ABBV AbbVie Inc. | $262.82 | $271.97 | +3.5% | Fairly valued |
| JNJ Johnson & Johnson | $256.03 | $217.11 | -15.2% | Overvalued |
All general drug manufacturer stocks ranked by gap to fair value
When does BIIB report earnings, and how has the stock reacted?
Biogen's next earnings report is scheduled for 29 Oct 2026. Companies can move their dates.
Options prices on 2 Oct 2026 imply a move of about 5.1% in either direction through the nearest expiry, about 13 days out. That is the size the market is pricing, not a direction. BIIB's 30 day implied volatility works out to about 10.1% over one month.
How BIIB moved around its last 8 earnings reports
Each move runs from the last close before the report to the first close after it, so it covers companies that report before the open and after the close. The median size across these 8 reports, ignoring direction, was 3.7%.
| Report date | Two session move |
|---|---|
| 29 Jul 2026 | +1.1% |
| 29 Apr 2026 | +3.2% |
| 6 Feb 2026 | +4.6% |
| 30 Oct 2025 | +4.3% |
| 31 Jul 2025 | +4.2% |
| 1 May 2025 | +2.0% |
| 12 Feb 2025 | -0.7% |
| 30 Oct 2024 | -5.2% |
Biogen at a glance
Biogen Inc. is a leading biotechnology firm dedicated to the discovery, development, production, and distribution of treatments for complex neurological and neurodegenerative conditions.
- Market value
- $33.6B
- Sector
- Healthcare
- Industry
- General Drug Manufacturers
- Revenue expected, next twelve months
- $10.6B
- Consensus revenue growth, next fiscal year
- +6.5%
- Analysts with estimates
- 20
- Beta to the US market
- 0.28
- First valued by Faircurve
- 1 May 2026
How the fair value is worked out: the model prices Biogen on the value of the whole business, debt included, against the operating profit analysts expect next year (forward EV/EBITDA), runs 2,000 simulations across its inputs and takes the midpoint. The full method is documented here.
What changed in the latest valuation?
On 26 Sep 2026 the model's fair value for BIIB was $235.33. As of 29 Sep 2026 it is $236.19, a change of +0.4%. The model revalues every stock it covers each week, and again after an earnings report.
Questions about Biogen's valuation
Is Biogen stock undervalued or overvalued?
On Faircurve's model, BIIB reads as Fairly valued as of 29 Sep 2026. The model's fair value is $236.19 a share against a last close of $219.88, a gap of +7.4%.
What is BIIB's fair value?
$236.19 a share as of 29 Sep 2026, the midpoint of 2,000 simulations. The model's own 20th to 80th percentile range is $179.02 to $305.65.
What price range does the model give BIIB?
$200.84 to $257.60 over 63 trading days. Ranges built this way held the price 60% of the time across 3,330 past valuations, refreshed 26 Sep 2026.
When does Biogen report earnings next?
The next report is scheduled for 29 Oct 2026. Companies can move their dates.
How much has BIIB moved on past earnings reports?
Across its last 8 reports the median two session move was 3.7%, ignoring direction. The largest was -5.2% around the report of 30 Oct 2024.
How confident is the model in this valuation?
The model's evidence grade for BIIB is medium. The grade looks at how complete the inputs are, how many comparable companies there are and how closely they agree, and how wide the range of outcomes is. It is not a probability that the fair value is right, or that the price reaches it.