[Form 4] MONOLITHIC POWER SYSTEMS INC Insider Trading Activity

Rhea-AI Filing Summary

Monolithic Power Systems (MPWR) reported an insider transaction by its EVP, WW Sales & Marketing. On 11/05/2025, the reporting person sold 200 shares of common stock at $986.81 per share.

Following the transaction, the report lists beneficial ownership positions, including 183,306 shares direct and 44,930 shares held indirectly in the Sciammas Family Trust, among various other family trusts and accounts.

SEC Form 4

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
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).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

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)
11/05/2025

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	11/05/2025		S		200	D	$986.81	1,299	I	Rosalind Sciammas Brokerage Account
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								44,930	I	Sciammas Family Trust
Common Stock								183,306	D
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:

Remarks:

	/s/ Saria Tseng, attorney-in-fact for Mr. Maurice Sciammas	11/05/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did MPWR disclose in this Form 4?

An EVP, WW Sales & Marketing sold 200 shares of MPWR common stock at $986.81 on 11/05/2025.

Who is the reporting person and their role at MPWR?

The reporting person is an Officer, serving as EVP, WW Sales & Marketing.

What was the sale price per share?

The reported transaction price was $986.81 per share.

How many shares are listed as directly owned after the transaction?

The filing lists 183,306 shares as directly owned following the transaction.

Are there indirect holdings disclosed?

Yes. Indirect positions include 44,930 shares in the Sciammas Family Trust, alongside other family trusts and accounts.

Was the Form 4 filed by one or multiple reporting persons?

It was filed by one reporting person.