Theodore Blegen's Stock Award and Ownership Update

On October 25, 2025, Theodore Blegen, EVP and CFO of Monolithic Power Systems Inc, was awarded 87,690 shares of common stock as part of market-based restricted stock units (MSUs) granted on October 25, 2022. The award was contingent on achieving specific stock price targets and relative total stockholder return percentile rank over a three-year performance period. The Compensation Committee of the Board of Directors certified the achievement of these criteria, resulting in the shares fully vesting on October 25, 2025. Additionally, Blegen holds shares in irrevocable trusts for Theodore F. Blegen and Sarah N. Blegen, each with 5,331 shares. This filing updates Blegen's ownership status and details the stock award.