Deming Xiao - Oct 25, 2025 Form 4 Insider Report for MONOLITHIC POWER SYSTEMS INC (MPWR)

Role: EVP, Global Operations
Signature: /s/ Saria Tseng, attorney-in-fact for Mr. Deming Xiao
Stock symbol: MPWR
Transactions as of: Oct 25, 2025
Transactions value $: $0
Form type: 4
Date filed: 10/28/2025, 09:36 PM
Previous filing: Aug 12, 2025
Next filing: Oct 31, 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Xiao Deming	EVP, Global Operations	5808 LAKE WASHINGTON BLVD NE, KIRKLAND	/s/ Saria Tseng, attorney-in-fact for Mr. Deming Xiao	2025-10-27	0001308647

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	MPWR	Common Stock	Award	$0	+136K	+112.32%	$0.00	256K	Oct 25, 2025	Direct	F1
holding	MPWR	Common Stock						20.5K	Oct 25, 2025	by Spouse
holding	MPWR	Common Stock						4.34K	Oct 25, 2025	Christopher Chao Xiao 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 135,520 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 135,520 shares being awarded to the reporting person. All of the shares fully vested on October 25, 2025, pursuant to the grant agreement.