Prothena Corporation plc
PRTA Healthcare Biotechnology
Prothena Corporation plc’s revenue for fiscal 2025 (year ended December 2025) was $9.7 million, down 92.8% from fiscal 2024. In the quarter to June 2026, revenue fell 77.2%, EPS grew 84.6% and free cash flow grew 44.6%, each against the same quarter a year earlier. Insiders bought in the last twelve months.
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Prothena Corporation plc (PRTA) P/E ratio
Prothena Corporation plc has no meaningful P/E ratio: its trailing twelve-month earnings is negative. Over the past ten years it has ranged from 0.0× (October 2026) to 2,974× (September 2022) — the current reading is the lowest in ten years.
P/E ratio, daily
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Annual newest first
| Period | P/E ratio | Change |
|---|---|---|
| FY2025 | 0.0× | — |
| FY2024 | 0.0× | — |
| FY2023 | 0.0× | — |
| FY2022 | 0.0× | — |
| FY2021 | 35.5× | — |
| FY2020 | 0.0× | — |
| FY2019 | 0.0× | — |
| FY2018 | 0.0× | — |
| FY2017 | 0.0× | — |
| FY2016 | 0.0× | — |
Quarterly newest first
| Period | P/E ratio | Change |
|---|---|---|
| Jun 2026 | 0.0× | — |
| Mar 2026 | 0.0× | — |
| Dec 2025 | 0.0× | — |
| Sep 2025 | 0.0× | — |
| 42 more quarters | Free account |
Against its own ten years
P/E ratio against peers
| Company | P/E ratio |
|---|---|
| ENTX Entera Bio Ltd. compare | n/m |
| DMAC DiaMedica Therapeutics, Inc. compare | n/m |
| EDIT Editas Medicine, Inc. compare | n/m |
| TECX Tectonic Therapeutic, Inc. compare | n/m |
| RZLT Rezolute, Inc. compare | n/m |
| PRTA Prothena Corporation plc | n/m |
| CAPR Capricor Therapeutics, Inc. compare | n/m |
| ASMB Assembly Biosciences, Inc. compare | 22.3× |
| YDES YD Bio Limited compare | — |
| Biotechnology industry median | 8.6× |
| Healthcare sector median | 22.7× |
| Market median | 17.9× |
What P/E ratio is
Price to Earnings Ratio shows how much investors pay for each dollar of a company’s annual profit per share.
Stock Price ÷ EPS (Basic) (TTM)