[Form 4] Monolithic Power Systems, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Transaction overview: On 08/06/2025, Maurice Sciammas, EVP, WW Sales & Marketing of Monolithic Power Systems Inc. (MPWR), filed a Form 4 reporting non‑derivative transactions in MPWR common stock involving intra‑family trust transfers.

The filing reports transfers of 4,836 shares to the Sciammas Family Trust and transfers of 2,000, 1,418 and 1,418 shares from various Sciammas 2022 GRATs and 2022 Trusts for Oski Crew into the Sciammas Family Trust. The filing states no funds were exchanged and no sale occurred for those transfers. The Sciammas Family Trust is reported to beneficially own 44,930 shares following the reported transaction(s); other trusts show beneficial ownership figures of 13,727, 9,481 and 9,481 in the filing.

The form is signed by Saria Tseng as attorney‑in‑fact for Mr. Sciammas on 08/06/2025. No derivative transactions, option exercises or cash sales are reported in this filing.

Positive

• Transfers were internal and non‑sales: the filing explicitly states no funds were exchanged and no sale occurred for the reported transfers.
• Timely, formal disclosure: Form 4 filed and signed on 08/06/2025 by an attorney‑in‑fact, updating beneficial ownership as required under Section 16.

Negative

• None.

Insights

Financial Analyst

TL;DR: Insider reported intra‑family transfers of 9,672 shares on 08/06/2025; transfers were non‑sales with no cash exchanged.

The activity consists of non‑derivative transfers among family trusts rather than open‑market disposals, indicating estate/ownership structuring rather than liquidity‑driven selling. Reported beneficial ownership figures (e.g., Sciammas Family Trust 44,930 shares) provide updated concentration data for shareholder structure analysis. No change to derivative positions or option exercises is disclosed, limiting immediate market impact.

Corporate Governance Expert

TL;DR: Form 4 shows trustee‑executed reallocations across family trusts; document affirms compliance with Section 16 reporting.

The filing documents transfers executed by the reporting person as trustee and confirms transfers were not sales (no funds exchanged), reducing regulatory concern about undisclosed market activity. Signature by an attorney‑in‑fact is present and dated 08/06/2025. From a governance perspective, these are routine estate/trust reorganizations; the disclosure updates beneficial ownership but does not indicate management stock monetization.

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)

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)
08/06/2025

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	08/06/2025		G		4,836	A	$0(1)	44,930	I	Sciammas Family Trust
Common Stock	08/06/2025		G		2,000	D	$0(2)	13,727	I	Various Sciammas GRATs
Common Stock	08/06/2025		G		1,418	D	$0(3)	9,481	I	Maurice Sciammas Trust FBO Oski Crew
Common Stock	08/06/2025		G		1,418	D	$0(4)	9,481	I	Christina Sciammas Trust FBO Oski Crew
Common Stock								1,699	I	The Chloe Liliane Sciammas 2020 Irrevocable Trust
Common Stock								2,000	I	Rosalind Sciammas Family 2021 Trust
Common Stock								102,325	D
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								2,000	I	Peter Rafferty and Eric Toothill 2021Trust
Common Stock								1,699	I	The Joseph Roger Sciammas 2020 Irrevocable Trust
Common Stock								1,499	I	Clement Sciammas (Sibling) Brokerage Account

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. 4,836 shares were transferred to the Sciammas Family Trust, on which the reporting person is a Trustee, from two Sciammas 2022 GRATs, and two Sciammas 2022 Siblings GRATs, and two Sciammas 2022 Trusts for Oski Crew, on which the reporting person is a Trustee. No funds were exchanged and no sale of shares occurred in the transfer.

2. 2,000 shares were transferred out of two Sciammas 2022 GRATs and two Sciammas 2022 Siblings GRATs, on which the reporting person is a Trustee, to the Sciammas Family Trust, on which the reporting person is a Trustee. No funds were exchanged and no sale of shares occurred in the transfer.

3. 1,418 shares were transferred out of the Maurice Sciammas 2022 Trust for Oski Crew, on which the reporting person is a Trustee, to the Sciammas Family Trust, on which the reporting person is a Trustee. No funds were exchanged and no sale of shares occurred in the transfer.

4. 1,418 shares were transferred out of the Christina Sciammas 2022 Trust for Oski Crew, on which the reporting person is a Trustee, to the Sciammas Family Trust, on which the reporting person is a Trustee. No funds were exchanged and no sale of shares occurred in the transfer.

Remarks:

	/s/ Saria Tseng, attorney-in-fact for Mr. Maurice Sciammas	08/06/2025
	** 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 Maurice Sciammas report on the MPWR Form 4 filed 08/06/2025?

He reported non‑derivative transfers of MPWR common stock among family trusts, including transfers of 4,836, 2,000, 1,418 and 1,418 shares.

Were the transfers reported on the Form 4 sales for cash?

No. The filing states that no funds were exchanged and no sale occurred for the reported transfers.

How many shares does the Sciammas Family Trust beneficially own following the transaction?

The filing reports the Sciammas Family Trust beneficially owns 44,930 shares following the reported transaction(s).

Did the Form 4 report any derivative transactions or option exercises?

No. Table II for derivative securities contains no entries; only non‑derivative common stock transfers are reported.

Who signed the Form 4 and when?

The form is signed by Saria Tseng, attorney‑in‑fact for Mr. Maurice Sciammas and dated 08/06/2025.