Dimensional Fund Advisors LP Reports New 5.2% Stake in Amphastar Pharmaceuticals Inc (AMPH)

On July 14, 2026, Dimensional Fund Advisors LP filed a Schedule 13G with the SEC, reporting a new 5.2% stake in Amphastar Pharmaceuticals Inc (AMPH). As of the event date of June 30, 2026, the investment management firm reported beneficial ownership of 2,305,107 shares of common stock. Dimensional Fund Advisors LP serves as an investment adviser to various registered investment companies, trusts, and separate accounts, through which it possesses voting and investment power over these securities. Specifically, the filer holds sole voting power over 2,251,660 shares and sole dispositive power over the full 2,305,107 shares. The filing indicates that the shares were acquired in the ordinary course of business and not for the purpose of influencing or changing the control of the issuer. Dimensional Fund Advisors LP formally disclaims beneficial ownership of these securities, noting that they are owned by the underlying funds it manages. This filing marks a significant increase from a previous 0.0% position.