Mr. Deming Xiao - 03 Feb 2026 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
Issuer symbol: MPWR
Transactions as of: 03 Feb 2026
Net transactions value: $0
Form type: 4
Filing time: 05 Feb 2026, 19:36:09 UTC
Previous filing: 31 Oct 2025
Next filing: 10 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Xiao Deming	EVP, Global Operations	1555 PALM BEACH LAKES BLVD., WEST PALM BEACH	/s/ Saria Tseng, attorney-in-fact for Mr. Deming Xiao	03 Feb 2026	0001308647

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	MPWR	Common Stock	Award	$0	+57,170	+28%	$0.000000	258,807	03 Feb 2026	Direct	F1
holding	MPWR	Common Stock						20,455	03 Feb 2026	by Spouse
holding	MPWR	Common Stock						4,336	03 Feb 2026	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 February 7, 2023, the reporting person was granted performance-based restricted stock units ("PSUs") subject to the achievement of performance conditions over a three-year performance period. On February 3, 2026, the Company's Compensation Committee of the Board of Directors certified and approved the achievement of the performance criteria for the PSUs, which resulted in 57,170 shares being awarded to the reporting person, subject to tax withholdings. All of the shares fully vested and were released on February 3, 2026, pursuant to the grant agreement.

Content

On February 7, 2023, the reporting person was granted performance-based restricted stock units ("PSUs") subject to the achievement of performance conditions over a three-year performance period. On February 3, 2026, the Company's Compensation Committee of the Board of Directors certified and approved the achievement of the performance criteria for the PSUs, which resulted in 57,170 shares being awarded to the reporting person, subject to tax withholdings. All of the shares fully vested and were released on February 3, 2026, pursuant to the grant agreement.