Mr. Robert W. Dean II - 27 Feb 2026 Form 3 Insider Report for MONOLITHIC POWER SYSTEMS INC (MPWR)

Role: Interim CFO
Signature: /s/ Saria Tseng, attorney-in-fact for Mr. Robert W. Dean II
Issuer symbol: MPWR
Transactions as of: 27 Feb 2026
Net transactions value: $0
Form type: 3
Filing time: 09 Mar 2026, 19:05:54 UTC
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
DEAN ROBERT W II	Interim CFO	1555 PALM BEACH LAKES BLVD., WEST PALM BEACH	/s/ Saria Tseng, attorney-in-fact for Mr. Robert W. Dean II	09 Mar 2026	0001445300

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
holding	MPWR	Common Stock						8,060	27 Feb 2026	Direct	F1
holding	MPWR	Common Stock						65	27 Feb 2026	Held by Parent & Daughter

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Includes an aggregate of 1,420 shares of restricted stock units that vest, subject to continued employment, as follows: 11 shares on 05/15/2026; 59 shares on 05/22/2026; 11 shares on 08/15/2026; 61 shares on 08/22/2026; 12 shares on 11/15/2026; 59 shares on 11/22/2026; 400 shares on 02/03/2027; 11 shares on 02/15/2027; 63 shares on 02/22/2027; 12 shares on 05/15/2027; 39 shares on 05/22/2027; 11 shares on 08/15/2027; 39 shares on 08/22/2027; 12 shares on 11/15/2027; 39 shares on 11/22/2027; 400 shares on 02/03/2028; 11 shares on 02/15/2028; 40 shares on 02/22/2028; 11 shares on 05/15/2028; 9 shares on 05/22/2028; 12 shares on 08/15/2028; 10 shares on 08/22/2028; 11 shares on 11/15/2028; 9 shares on 11/22/2028; 12 shares on 02/15/2029; 10 shares on 02/22/2029; 11 shares on 05/15/2029; 12 shares on 08/15/2029; 11 shares on 11/15/2029; and 12 shares on 02/15/2030.

Content

Includes an aggregate of 1,420 shares of restricted stock units that vest, subject to continued employment, as follows: 11 shares on 05/15/2026; 59 shares on 05/22/2026; 11 shares on 08/15/2026; 61 shares on 08/22/2026; 12 shares on 11/15/2026; 59 shares on 11/22/2026; 400 shares on 02/03/2027; 11 shares on 02/15/2027; 63 shares on 02/22/2027; 12 shares on 05/15/2027; 39 shares on 05/22/2027; 11 shares on 08/15/2027; 39 shares on 08/22/2027; 12 shares on 11/15/2027; 39 shares on 11/22/2027; 400 shares on 02/03/2028; 11 shares on 02/15/2028; 40 shares on 02/22/2028; 11 shares on 05/15/2028; 9 shares on 05/22/2028; 12 shares on 08/15/2028; 10 shares on 08/22/2028; 11 shares on 11/15/2028; 9 shares on 11/22/2028; 12 shares on 02/15/2029; 10 shares on 02/22/2029; 11 shares on 05/15/2029; 12 shares on 08/15/2029; 11 shares on 11/15/2029; and 12 shares on 02/15/2030.