X0508 4 2024-06-17 0 0001394056 ONE STOP SYSTEMS, INC. OSS 0001755059 KNOWLES MICHAEL 2235 ENTERPRISE STREET, SUITE 110 ESCONDIDO CA 92029 1 1 0 0 Chief Executive Officer 0 Common Stock 2024-06-17 4 F 0 38050 2.18 D 363080 D The Reporting Person forfeited 38,050 shares of common stock upon conversion of 100,000 vested and outstanding Restricted Stock Units into shares of common stock to cover tax withholdings, using the market price of the issuer's common stock at the time of forfeiture. These Restricted Stock Units were part of the grant reported in Table I of the Form 4 filed by the Reporting Person with the Securities and Exchange Commission on June 6, 2023. Includes 300,000 unvested restricted stock units held by the Reporting Person, all of which remain subject to certain vesting conditions. /s/ Michael Knowles 2024-06-18