FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Expires: December 31, 2014 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person * Sciammas Maurice (Last) (First) (Middle) 5808 LAKE WASHINGTON BLVD NE (Street) KIRKLAND WA 98033 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol MONOLITHIC POWER SYSTEMS INC [ MPWR ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director 10% Owner X Officer (give title below) Other (specify below) EVP, WW Sales & Marketing
	3. Date of Earliest Transaction (Month/Day/Year) 10/25/2025
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	10/25/2025		A		135,520 (1)	A	$ 0	237,849 (2)	D
Common Stock								9,481	I	Maurice Sciammas Trust FBO Oski Crew
Common Stock								1,699	I	The Joseph Roger Sciammas 2020 Irrevocable Trust
Common Stock								2,000	I	Rosalind Sciammas Family 2021 Trust
Common Stock								9,481	I	Christina Sciammas Trust FBO Oski Crew
Common Stock								1,499	I	Clement Sciammas Brokerage Account
Common Stock								1,499	I	Rosalind Sciammas Brokerage Account
Common Stock								44,930	I	Sciammas Family Trust
Common Stock								12,228	I	Various Sciammas GRATs
Common Stock								1,699	I	The Patrick Francis Sciammas 2020 Irrevocable Trust
Common Stock								4,015	I	By Sciammas Trust 2020
Common Stock								5,000	I	Clement Sciammas Family 2021 Trust
Common Stock								1,000	I	Peter Rafferty and Eric Toothill 2021Trust
Common Stock								1,699	I	The Chloe Liliane Sciammas 2020 Irrevocable Trust

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. On October 25, 2022, the reporting person was granted market-based restricted stock units ("MSUs") subject to the achievement of five stock price targets and relative total stockholder return percentile rank over a three-year performance and vesting period. On October 25, 2025, the Company's Compensation Committee of the Board of Directors certified and approved the achievement of the performance criteria for the MSUs, which resulted in 135,520 shares being awarded to the reporting person. All of the shares fully vested on October 25, 2025, pursuant to the grant agreement.

2. Ending balance includes 4 shares acquired on August 15, 2025 through the Company's qualified ESPP program.

	/s/ Saria Tseng, attorney-in-fact for Mr. Maurice Sciammas	10/27/2025
	** Signature of Reporting Person	Date
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