[Form 4] MONOLITHIC POWER SYSTEMS INC Insider Trading Activity

Rhea-AI Filing Summary

Monolithic Power Systems (MPWR)11/19/2025. Across a series of trades, he sold a total of 7,034 shares at weighted average prices reported between about $862 and $875 per share, with detailed price ranges noted for each trade.

After these transactions, Sciammas directly owned 176,272 shares of MPWR common stock and also had additional indirect holdings through various family trusts and accounts, including positions such as 49,460 shares in the Sciammas Family Trust and other named family and irrevocable trusts. The footnotes state that the reported prices are weighted averages and that full trade-by-trade price information is available upon request.

11/20/2025 - 04:47 PM

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
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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)

1555 PALM BEACH LAKES BLVD.

(Street)

WEST PALM BEACH WA 33401

(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)
11/19/2025

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	11/19/2025		S		240	D	$862.58(1)	183,066	D
Common Stock	11/19/2025		S		160	D	$863.86	182,906	D
Common Stock	11/19/2025		S		40	D	$865.89	182,866	D
Common Stock	11/19/2025		S		339	D	$866.19(2)	182,527	D
Common Stock	11/19/2025		S		699	D	$867.57(3)	181,828	D
Common Stock	11/19/2025		S		723	D	$868.42(4)	181,105	D
Common Stock	11/19/2025		S		1,842	D	$869.39(5)	179,263	D
Common Stock	11/19/2025		S		320	D	$870.36(6)	178,943	D
Common Stock	11/19/2025		S		220	D	$871.45(7)	178,723	D
Common Stock	11/19/2025		S		574	D	$872.8(8)	178,149	D
Common Stock	11/19/2025		S		1,146	D	$873.78(9)	177,003	D
Common Stock	11/19/2025		S		731	D	$874.5(10)	176,272	D
Common Stock								1,699	I	The Joseph Roger Sciammas 2020 Irrevocable Trust
Common Stock								2,000	I	Rosalind Sciammas Family 2021 Trust
Common Stock								1,299	I	Rosalind Sciammas Brokerage Account
Common Stock								49,460	I	Sciammas Family Trust
Common Stock								26,660	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
Common Stock								1,499	I	Clement Sciammas 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. 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 $862.25 to $862.75. 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.

2. 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 $866.16 to $866.51. 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.

3. 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 $867.04 to $867.98. 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.

4. 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 $868.00 to $868.94. 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.

5. 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 $869.00 to $869.91. 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.

6. 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 $870.07 to $870.98. 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.

7. 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 $871.39 to $871.64. 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.

8. 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 $872.74 to $872.89. 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.

9. 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 $873.49 to $873.97. 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.

10. 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 $874.09 to $874.90. 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.

Remarks:

	/s/ Saria Tseng, attorney-in-fact for Mr. Maurice Sciammas	11/19/2025
	** 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.