Prothena Plc (PRTA) returns
Prothena Plc returns over 10 years
$1,000 invested in Prothena Plc ten years ago was worth $164.31 at the close on October 30, 2026, with dividends reinvested: an average return of -16.5% a year. The same $1,000 in the S&P 500 (SPY) became $4,166.
Total return by period
| Period | Total return | A year, on average | $1,000 became | S&P 500 (SPY) |
|---|---|---|---|---|
| 1 month | +1.1% | — | $1,011 | -0.9% |
| 3 months | +0.7% | — | $1,007 | +2.1% |
| Year to date | -11.3% | — | $886.91 | +11.7% |
| 1 year | -19.2% | — | $808.21 | +12.4% |
| 3 years | -76.1% | -38.0% | $238.79 | +88.5% |
| 5 years | -84.7% | -31.3% | $153.03 | +76.0% |
| 10 years | -83.6% | -16.5% | $164.31 | +316.6% |
Prothena Plc return by calendar year
| Year | PRTA | S&P 500 (SPY) | Difference |
|---|---|---|---|
| 2026 to date | -11.3% | +11.7% | -23.0% |
| 2025 | -31.0% | +17.7% | -48.8% |
| 2024 | -61.9% | +24.9% | -86.8% |
| 2023 | -39.7% | +26.2% | -65.9% |
| 2022 | +22.0% | -18.2% | +40.1% |
| 2021 | +311.3% | +28.7% | +282.6% |
| 2020 | -24.1% | +18.4% | -42.5% |
| 2019 | +53.7% | +31.2% | +22.5% |
| 2018 | -72.5% | -4.6% | -68.0% |
| 2017 | -23.8% | +21.7% | -45.5% |
| 2016 | -27.8% | +12.0% | -39.8% |
Past returns do not predict future returns. Returns are computed from our daily closes, adjusted for splits and with dividends reinvested on their ex-dates; taxes and trading costs are left out.
See also: PRTA financials
No forecast, no recommendation. This page describes Prothena Plc from published data; it is not advice to buy, sell or hold any security.
Figures as of the close on Oct 30, 2026 unless a row says otherwise. Prices are split adjusted; returns include dividends reinvested. Data may be delayed. See the disclaimer and how TrendArc works.