Assembly Biosciences (ASMB) vs Prothena (PRTA)
Head-to-head comparison of performance, valuation, growth, profitability and dividends. Prices delayed 15 minutes; data as of Oct 8, 2026.
Summary
Assembly Biosciences (ASMB) has outperformed Prothena (PRTA) over the past year, losing 3.8% versus a loss of 16.6%. Over five years, ASMB leads with a -41.3% price change compared with -86.6% for PRTA. Assembly Biosciences is the larger company by market cap ($467.3 million vs $435.3 million), about 1.1 times the size.
Summary generated from market data by MetaCap's automated system. Methodology
Relative performance
Percent change in share price from the first common trading day shown; excludes dividends.
Head-to-head
| Metric | ASMB | PRTA |
|---|---|---|
| Share price | $22.95 | $8.48 |
| Market cap | $467.28M | $435.34M |
| 1-day change | +3.47% | +5.74% |
| YTD return | -32.52% | -11.20% |
| 1-year return | -3.81% | -16.62% |
| 5-year return | -41.33% | -86.64% |
| P/E ratio (TTM) | 21.25 | — |
| EPS (TTM) | $1.08 | $-0.82 |
| Dividend yield | 0.00% | 0.00% |
| Annual dividend | $0.00 | $0.00 |
| 52-week high | $39.71 | $11.80 |
| 52-week low | $21.80 | $7.73 |
| Distance from 52-week high | -42.21% | -28.14% |
| Analyst consensus | none | none |
| Avg. price target upside | +126.58% | +152.36% |
| Average volume | 277.22K | 478.70K |
| Shares outstanding | 20.36M | 51.34M |
| Employees | 73 | 67 |
| Sector | Healthcare | Healthcare |
| Industry | Biotechnology | Biotechnology |
Highlighted cells mark the higher value for growth, returns, margins and yield, and the lower value for P/E ratios. Highlighting is a mechanical comparison, not a recommendation.
Key differences
- ASMB has outperformed PRTA by 12.8 percentage points over the past year.
About Assembly Biosciences
ASMB stock →Assembly Biosciences, Inc., a biotechnology company, develops therapeutic candidates for the treatment of viral diseases worldwide. Its pipeline includes long-acting helicase-primase inhibitors candidates, including ABI-5366 and ABI-1179, which are in Phase 1 clinical studies for recurrent genital herpes; and ABI-6250, an orally bioavailable hepatitis delta virus entry inhibitor that is in Phase 1a clinical study for the treatment of chronic hepatitis delta virus (HDV) infection.
Healthcare · Biotechnology · 73 employees
About Prothena
PRTA stock →Prothena Corporation plc, a late-stage clinical biotechnology company, focuses on discovery and development of novel therapies to treat diseases caused by protein dysregulation. Its product pipeline includes Prasinezumab, an investigational humanized monoclonal antibody which is in Phase 3 clinical trial for the treatment of parkinson's disease and other synucleinopathies.
Healthcare · Biotechnology · 67 employees
ASMB vs PRTA FAQ
Which is bigger, Assembly Biosciences or Prothena?
Assembly Biosciences (ASMB) is larger, with a market capitalization of $467.28M compared with $435.34M for Prothena (PRTA).
Which stock has performed better over the past year, ASMB or PRTA?
ASMB returned -3.81% over the past 12 months, compared with -16.62% for PRTA (price return, excluding dividends). Past performance does not predict future results.
Are Assembly Biosciences and Prothena in the same industry?
Yes. Both are classified in the Biotechnology industry within the Healthcare sector.