Michael Hsing - 25 Oct 2025 Form 4 Insider Report for MONOLITHIC POWER SYSTEMS INC (MPWR)

Role: CEO, Director
Signature: /s/ Saria Tseng, attorney-in-fact for Mr. Michael R. Hsing
Issuer symbol: MPWR
Transactions as of: 25 Oct 2025
Transactions value $: $0
Form type: 4
Filing time: 28 Oct 2025, 21:37:20 UTC
Previous filing: 18 Aug 2025
Next filing: 31 Oct 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Hsing Michael	CEO, Director	5808 LAKE WASHINGTON BLVD NE, KIRKLAND	/s/ Saria Tseng, attorney-in-fact for Mr. Michael R. Hsing	27 Oct 2025	0001308676

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	MPWR	Common Stock	Award	$0	+303K	+37.18%	$0.00	1.12M	25 Oct 2025	Direct	F1
holding	MPWR	Common Stock						133K	25 Oct 2025	by M Hsing 04 Trust
holding	MPWR	Common Stock						12.8K	25 Oct 2025	ZH Family 2020 Trust

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

Explanation of Responses:

Id	Content
F1	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 302,920 shares being awarded to the reporting person. All of the shares fully vested on October 25, 2025, pursuant to the grant agreement.

Content

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 302,920 shares being awarded to the reporting person. All of the shares fully vested on October 25, 2025, pursuant to the grant agreement.