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: 2026-05-26 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: 2026-05-26 | Code: S (Open market sale) Shares: -22 | Price: $1,649.56 Total Value: $36,290.32 Shares Owned After: 5,878 | Ownership: D (Direct) Footnotes: [F1] The reported sale was to cover tax withholding obligations upon the vesting of restricted stock units. [F2] The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,647.84 to $1,650.16. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. --- Holdings --- [Holding #1] Security: Common Stock Ownership: I (Indirect) --- Footnotes (Complete Index) --- F1: The reported sale was to cover tax withholding obligations upon the vesting of restricted stock units. F2: The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,647.84 to $1,650.16. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. --- Signature --- /s/ /s/ Saria Tseng, attorney-in-fact for Mr. Robert W. Dean II (2026-05-28)