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: 2026-06-01 10b5-1 Pre-arranged Plan: Yes --- Issuer --- Name: MONOLITHIC POWER SYSTEMS INC (MPWR) CIK: 0001280452 --- Reporting Owner --- Name: Sciammas Maurice CIK: 0001360833 Role: Officer (EVP, WW Sales & Marketing) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-06-01 | Code: S (Open market sale) Shares: -30 | Price: $1,533.95 Total Value: $46,018.50 Shares Owned After: 1,179 | Ownership: I (Indirect) | Nature: Clement Sciammas Trust Footnotes: [F1] This transaction was made pursuant to a Rule 10b5-1 trading plan adopted on 11/19/2025. --- Holdings --- [Holding #1] Security: Common Stock Ownership: D (Direct) [Holding #2] Security: Common Stock Ownership: I (Indirect) [Holding #3] Security: Common Stock Ownership: I (Indirect) [Holding #4] Security: Common Stock Ownership: I (Indirect) [Holding #5] Security: Common Stock Ownership: I (Indirect) [Holding #6] Security: Common Stock Ownership: I (Indirect) [Holding #7] Security: Common Stock Ownership: I (Indirect) [Holding #8] Security: Common Stock Ownership: I (Indirect) [Holding #9] Security: Common Stock Ownership: I (Indirect) [Holding #10] Security: Common Stock Ownership: I (Indirect) [Holding #11] Security: Common Stock Ownership: I (Indirect) --- Footnotes (Complete Index) --- F1: This transaction was made pursuant to a Rule 10b5-1 trading plan adopted on 11/19/2025. --- Signature --- /s/ /s/ Saria Tseng, attorney-in-fact for Mr. Maurice Sciammas (2026-06-03)