P/E ratio for Prothena (PRTA)
P/E ratio as of April 2025 (TTM): -3.35
According to Prothena's latest financial reports and stock price the company's current price-to-earnings ratio (TTM) is -3.34783. At the end of 2022 the company had a P/E ratio of -24.1.
P/E ratio history for Prothena from 2012 to 2023
PE ratio at the end of each year
| Year | P/E ratio | Change |
|---|---|---|
| 2022 | -24.1 | -167.81% |
| 2021 | 35.5 | -925.61% |
| 2020 | -4.30 | -46.97% |
| 2019 | -8.12 | 210.53% |
| 2018 | -2.61 | -71.69% |
| 2017 | -9.23 | -12.52% |
| 2016 | -10.6 | -59.24% |
| 2015 | -25.9 | -90.02% |
| 2014 | -260 | 2072.29% |
| 2013 | -11.9 | 302.73% |
| 2012 | -2.97 |
P/E ratio for similar companies or competitors
| Company | P/E ratio | P/E ratio differencediff. | Country |
|---|---|---|---|
 | 20.6 | -715.44% | 🇮🇪 Ireland |
 | -56.5 | 1,586.82% | 🇺🇸 USA |
 | -74.3 | 2,119.40% | 🇮🇪 Ireland |
How to read a P/E ratio?
The Price/Earnings ratio measures the relationship between a company's stock price and its earnings per share. A low but positive P/E ratio stands for a company that is generating high earnings compared to its current valuation and might be undervalued. A company with a high negative (near 0) P/E ratio stands for a company that is generating heavy losses compared to its current valuation.
Companies with a P/E ratio over 30 or a negative one are generaly seen as "growth stocks" meaning that investors typically expect the company to grow or to become profitable in the future.
Companies with a positive P/E ratio bellow 10 are generally seen as "value stocks" meaning that the company is already very profitable and unlikely to strong growth in the future.