Biogen vs Gilead Sciences (BIIB vs GILD)
Side by side from their SEC filings: revenue, margins, growth, returns and valuation, plus short interest, insider activity and institutional ownership.
Gilead Sciences is the larger company by revenue ($29.4B vs $9.9B) and market value ($161.2B vs $30.9B). Gilead Sciences has grown revenue faster over the last 4 fiscal years (+7.8% cumulative vs -9.9%). Gilead Sciences trades at the lower trailing P/E (17.7x vs 22.5x).
About Biogen
Biogen Inc. is a global biopharmaceutical company that discovers, develops, and delivers therapies for serious and complex diseases. It markets treatments for multiple sclerosis, spinal muscular atrophy, Friedreich's ataxia, amyotrophic lateral sclerosis, and collaborates on therapies for Alzheimer's disease and other conditions. The company also develops biosimilars and engages in research collaborations and acquisitions to advance its pipeline in neurology, immunology, and rare diseases.
About Gilead Sciences
Gilead Sciences, Inc. is a biopharmaceutical company that develops and markets medicines to treat life-threatening diseases such as HIV, viral hepatitis, COVID-19, and cancer. Its product portfolio includes oral antiretroviral therapies for HIV, treatments for liver diseases like hepatitis B and C, oncology therapies including CAR T-cell treatments, and antifungal and antiviral drugs. The company serves healthcare providers and patients worldwide through its commercial operations in over 35 countries.
Head to head (BIIB FY2025 vs GILD FY2025)
| Metric | BIIBFY2025 | GILDFY2025 |
|---|---|---|
| Revenue | $9.89B | $29.44B |
| Revenue growth (YoY) | 2.2% | 2.4% |
| Gross margin | 75.7% | 78.8% |
| Operating margin | — | 34.0% |
| Net margin | 13.1% | 28.9% |
| Net income | $1.29B | $8.51B |
| Diluted EPS | $8.79 | $6.78 |
| FCF margin | 20.7% | 32.1% |
| ROE | 7.1% | 37.6% |
| Debt / equity | 0.3× | 1.0× |
| Market cap | $30.86B | $161.19B |
| P/E (TTM) | 22.5× | 17.7× |
Fundamentals are from each company’s SEC filings (BIIB FY2025, GILD FY2025). P/E and market cap are derived from recent market prices and update daily.
Five-year trend (as reported)
| Revenue | FY2021 | FY2022 | FY2023 | FY2024 | FY2025 |
|---|---|---|---|---|---|
| BIIB | $10.98B | $10.17B | $9.84B | $9.68B | $9.89B |
| GILD | $27.30B | $27.28B | $27.12B | $28.75B | $29.44B |
Peer standing
Where each company ranks among the 71 biotech companies, on the same scale. Each figure is ranked only against peers that report it. Percentiles describe position in the distribution, not a rating.
| Metric | BIIB | GILD |
|---|---|---|
| Gross margin | 75.7%77th percentile of 14 | 78.8%85th percentile of 14 |
| Net margin | 13.1%58th percentile of 32 | 28.9%81st percentile of 32 |
| FCF margin | 20.7%63rd percentile of 28 | 32.1%81st percentile of 28 |
| Revenue growth (YoY) | +2.2%32nd percentile of 64 | +2.4%33rd percentile of 64 |
| ROE | 7.1%77th percentile of 61 | 37.6%92nd percentile of 61 |
| P/E (TTM) | 22.5×65th percentile of 21 | 17.7×50th percentile of 21 |
| Debt / equity | 0.34×56th percentile of 19 | 0.98×78th percentile of 19 |
| Short interest (days to cover) | 4.14d43rd percentile of 71 | 2.66d23rd percentile of 71 |
Short interest
| FINRA settlement data | BIIB | GILD |
|---|---|---|
| Shares sold short | 5.7M | 25.5M |
| Change vs prior settlement | +10.3% | +6.8% |
| Days to cover | 4.14 | 2.66 |
| As of settlement | 2026-06-30 | 2026-06-30 |
Source: FINRA Consolidated Short Interest. FINRA is the owner and source of the FINRA-supplied data; republishing or redistributing it is not permitted. Not presented as a percentage of float. No FINRA endorsement of this product is implied.
Insider activity (last 90 days)
| Form 4 open-market activity | BIIB | GILD |
|---|---|---|
| Buys | — | 0 |
| Sells | — | 18 ($10.8M) |
Open-market purchases and sales reported on SEC Form 4 (grants, exercises and tax withholding excluded). For context, about 16% of covered companies saw any open-market insider buy in a 90-day window.
Held by the same investors
7 tracked 13F managers hold both Biogen and Gilead Sciences as of their latest quarterly filings: AQR Capital Management, Citadel Advisors, Gotham Asset Management, Millennium Management, Point72 Asset Management, Renaissance Technologies, Two Sigma Investments. See which superinvestors hold your own portfolio with the smart money checker.
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Data sourced from SEC EDGAR (public domain). Figures are as-reported and may be unaudited or restated; verify against the source filings before relying on them. Comparisons are descriptive (higher or lower on a reported figure), not a rating or a recommendation. Informational only. Not investment advice.