Biogen (BIIB)
What the price implies
A reverse DCF: instead of guessing a fair value, it asks what growth today's price already assumes. How it works.
At a market value of $31.4B, Biogen's free cash flow of $2.1B (fiscal 2025) would need to grow about 2% a year for the stock to be worth today's price. That is faster than the company has grown its free cash flow over the last 9 years.
Assumes a 9% discount rate and 3% growth after year 10, on free cash flow (operating cash flow minus capital spending) from Biogen's SEC filings. Change any assumption, or model revenue and margins instead, in the Modeling tab, or try your own numbers in the reverse DCF calculator.
Fundamental grade
Five factors scored 1 to 9 from BIIB's latest numbers, weighted into one grade. It describes the business, not whether the stock is a buy.
Key numbers
Results from SEC filings
Fiscal years, from Biogen's 10-K filings. The deep dive has 15+ years, quarters and every line.
| Fiscal year | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|
| Revenue | $11.0B | $10.2B | $9.8B | $9.7B | $9.9B |
| Net income | $1.6B | $3.0B | $1.2B | $1.6B | $1.3B |
| Free cash flow | $3.4B | $1.1B | $1.3B | $2.7B | $2.1B |
| EPS (diluted) | $10.40 | $20.87 | $7.97 | $11.18 | $8.79 |
| Operating margin | 25.9% | 35.3% | 13.2% | 19.7% | 15.7% |
Where the revenue comes from
Revenue by products, fiscal 2025.
Superinvestors who own BIIB
From each investor's latest 13F filing (what a 13F shows). 5 of the investors we track hold it.
| Investor | Last quarter | Value | % of portfolio | Quarter |
|---|---|---|---|---|
| PRIMECAP Management PRIMECAP Management Co |
Added | $3.3B | 1.9% | Q2 2026 |
| Cliff Asness AQR Capital Management |
Added | $417M | 0.14% | Q2 2026 |
| Joel Greenblatt Gotham Asset Management |
Trimmed | $60M | 0.14% | Q2 2026 |
| Tom Steyer Farallon Capital Management LLC |
New position | $15M | 0.07% | Q2 2026 |
| Murray Stahl Horizon Kinetics LLC |
Trimmed | $588,980 | 0.01% | Q2 2026 |
Insider buying
Open-market purchases by Biogen's executives and directors in the last 12 months, from SEC Form 4 filings. What insider buying tells you.
| Date | Insider | Shares | Price | Value |
|---|---|---|---|---|
| Feb 12, 2026 | Nicole Murphy |
3 | $195.03 | $585 |
| Jan 30, 2026 | Gilbert Ray Cisneros, Jr. |
0 | $179.89 | — |
| Jan 30, 2026 | Gilbert Ray Cisneros, Jr. |
0 | $179.89 | — |
| Jan 29, 2026 | Ro Khanna |
0 | $176.18 | — |
| Jan 29, 2026 | Ro Khanna |
0 | $176.18 | — |
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In the full deep dive
Questions
What growth does Biogen's stock price imply?
At a market value of $31.4B, Biogen would need its free cash flow to grow about 2% a year for 10 years (discounted at 9%, 3% growth after that) to be worth today's price. Over the last 9 years its free cash flow grew -7% a year.
Are Biogen insiders buying the stock?
5 open-market insider purchases of BIIB in the last 12 months, from SEC Form 4 filings.
Which superinvestors own Biogen?
5 of the superinvestors Investingly tracks hold BIIB in their latest 13F, including PRIMECAP Management, Cliff Asness, Joel Greenblatt.
Prices and ratios as of Oct 7, 2026; statements from SEC filings. Information only, not investment advice. Superinvestor holdings come from 13F filings, which are filed up to 45 days after each quarter ends.