Prothena - 13 Year Stock Price History | PRTA

The latest closing stock price for Prothena as of July 29, 2025 is 6.93.

  • An investor who bought $1,000 worth of Prothena stock at the IPO in 2012 would have $-38 today, roughly 0 times their original investment - a -0.29% compound annual growth rate over 13 years.
  • The all-time high Prothena stock closing price was 78.89 on September 23, 2021.
  • The Prothena 52-week high stock price is 23.66, which is 241.4% above the current share price.
  • The Prothena 52-week low stock price is 4.32, which is 37.7% below the current share price.
  • The average Prothena stock price for the last 52 weeks is 13.43.
For more information on how our historical price data is adjusted see the Stock Price Adjustment Guide.

Prothena - 13 Year Stock Price History | PRTA

  • An investor who bought $1,000 worth of Prothena stock at the IPO in 2012 would have $-38 today, roughly 0 times their original investment - a -0.29% compound annual growth rate over 13 years.
  • The all-time high Prothena stock closing price was 78.89 on September 23, 2021.
  • The Prothena 52-week high stock price is 23.66, which is 241.4% above the current share price.
  • The Prothena 52-week low stock price is 4.32, which is 37.7% below the current share price.
  • The average Prothena stock price for the last 52 weeks is 13.43.
For more information on how our historical price data is adjusted see the Stock Price Adjustment Guide.