Monolithic Power Systems (MPWR) EVP gains 57,170 performance-based shares

Rhea-AI Filing Summary

Monolithic Power Systems executive Deming Xiao reported a stock award tied to prior performance-based incentives. As EVP, Global Operations, he received 57,170 shares of common stock on February 3, 2026 at $0 per share, following the certification of performance-based restricted stock units granted in 2023. After this vesting, he beneficially owns 258,807 shares directly, plus 20,455 shares held indirectly by his spouse and 4,336 shares held indirectly through the Christopher Chao Xiao Trust.

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

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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^*

Xiao Deming

(Last) (First) (Middle)

1555 PALM BEACH LAKES BLVD.

(Street)

WEST PALM BEACH FL 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, Global Operations

3. Date of Earliest Transaction (Month/Day/Year)
02/03/2026

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	02/03/2026		A		57,170(1)	A	$0	258,807	D
Common Stock								20,455	I	by Spouse
Common Stock								4,336	I	Christopher Chao Xiao 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. 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.

Remarks:

	/s/ Saria Tseng, attorney-in-fact for Mr. Deming Xiao	02/03/2026
	** 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 insider transaction did MPWR executive Deming Xiao report?

Deming Xiao reported a grant of 57,170 shares of Monolithic Power Systems common stock. These shares resulted from performance-based restricted stock units granted in 2023, which fully vested after the company’s Compensation Committee certified that the performance conditions were achieved on February 3, 2026.

How many MPWR shares does Deming Xiao own after this Form 4 filing?

After the reported transaction, Deming Xiao beneficially owns 258,807 shares of Monolithic Power Systems directly. He also has indirect beneficial ownership of 20,455 shares held by his spouse and 4,336 shares held by the Christopher Chao Xiao Trust, as disclosed in the filing.

What triggered the 57,170-share award to MPWR executive Deming Xiao?

The 57,170-share award was triggered when Monolithic Power Systems’ Compensation Committee certified that performance criteria for previously granted PSUs were met. These PSUs were granted on February 7, 2023, with a three-year performance period, and fully vested and were released on February 3, 2026.

Was the MPWR stock award to Deming Xiao a cash purchase?

No, the 57,170 MPWR shares reported by Deming Xiao were acquired at a price of $0 per share. They were issued as a stock award upon vesting of performance-based restricted stock units, not bought in an open-market or cash purchase transaction.

How are Deming Xiao’s indirect MPWR share holdings structured?

Deming Xiao reports indirect beneficial ownership of MPWR shares through two relationships. One block of 20,455 shares is held by his spouse, and another block of 4,336 shares is held by the Christopher Chao Xiao Trust, both listed as indirect holdings in the Form 4.

What role does Deming Xiao hold at Monolithic Power Systems (MPWR)?

Deming Xiao serves as Executive Vice President, Global Operations at Monolithic Power Systems. His position and insider status require public reporting of changes in his beneficial ownership of company stock, such as the performance-based share award disclosed in this Form 4.