MONOLITHIC POWER SYSTEMS INC (MPWR) · Insider Trading (Form 4) SEC Filing

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-07-25 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: MONOLITHIC POWER SYSTEMS, INC. (MPWR) CIK: 0001280452 --- Reporting Owner --- Name: DEAN ROBERT W II CIK: 0001445300 Role: Officer (Interim CFO) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-07-25 | Code: A (Grant or award) Shares: +1,359 | Price: $0.00 Shares Owned After: 7,237 | Ownership: D (Direct) Footnotes: [F1] On July 25, 2023, the reporting person was granted market-based restricted stock units ("MSUs") subject to the achievement of stock price targets and relative total stockholder return percentile rank over a three-year performance period. On July 25, 2026, the Company's Compensation Committee of the Board of Directors certified and approved the achievement of the performance conditions for the MSUs, which resulted in an award of 1,359 shares to the reporting person. 1/3 of the shares will vest on July 25, 2027, 1/3 of the shares will vest on July 25, 2028, and 1/3 of the shares will vest on July 25, 2029, pursuant to the grant agreement. --- Holdings --- [Holding #1] Security: Common Stock Ownership: I (Indirect) --- Footnotes (Complete Index) --- F1: On July 25, 2023, the reporting person was granted market-based restricted stock units ("MSUs") subject to the achievement of stock price targets and relative total stockholder return percentile rank over a three-year performance period. On July 25, 2026, the Company's Compensation Committee of the Board of Directors certified and approved the achievement of the performance conditions for the MSUs, which resulted in an award of 1,359 shares to the reporting person. 1/3 of the shares will vest on July 25, 2027, 1/3 of the shares will vest on July 25, 2028, and 1/3 of the shares will vest on July 25, 2029, pursuant to the grant agreement. --- Signature --- /s/ /s/ Saria Tseng, attorney-in-fact for Mr. Robert W. Dean II (2026-07-28)