PSU payout gives Monolithic Power (MPWR) CEO 136,825 new shares

Rhea-AI Filing Summary

Monolithic Power Systems CEO Michael Hsing, who is also a director, reported the vesting of 136,825 shares of common stock on February 3, 2026. These shares came from performance-based restricted stock units granted on February 7, 2023 after a three-year performance period and were awarded at a price of $0 per share, subject to tax withholding.

After this award, Hsing directly beneficially owned 1,043,157 shares of common stock. In addition, indirect holdings totaled 133,040 shares through the M Hsing 04 Trust and 12,825 shares through the ZH Family 2020 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^*

Hsing Michael

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CEO

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		136,825(1)	A	$0	1,043,157	D
Common Stock								133,040	I	by M Hsing 04 Trust
Common Stock								12,825	I	ZH Family 2020 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 136,825 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. Michael R. Hsing	02/03/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transaction did MPWR CEO Michael Hsing report?

Michael Hsing reported the vesting of 136,825 shares of Monolithic Power Systems common stock. The shares came from performance-based restricted stock units granted in 2023, which were certified as earned and fully vested on February 3, 2026 after performance conditions were achieved.

When did the performance stock units for MPWR’s CEO fully vest?

The performance-based restricted stock units fully vested and were released on February 3, 2026. The company’s Compensation Committee certified achievement of the performance criteria the same day, ending a three-year performance period that began with the grant on February 7, 2023.

How many MPWR shares were awarded to CEO Michael Hsing from PSUs?

A total of 136,825 Monolithic Power Systems common shares were awarded to CEO Michael Hsing. These shares resulted from performance-based restricted stock units that paid out after the Compensation Committee confirmed that required performance conditions over the three-year period had been met.

What is Michael Hsing’s direct MPWR share ownership after this award?

After this PSU-related award, Michael Hsing directly beneficially owned 1,043,157 shares of Monolithic Power Systems common stock. This figure reflects his direct holdings following the vesting and release of 136,825 shares on February 3, 2026, as reported in the Form 4.

What indirect MPWR share holdings are reported for Michael Hsing?

The filing shows 133,040 Monolithic Power Systems shares held indirectly through the M Hsing 04 Trust. It also reports 12,825 shares held indirectly through the ZH Family 2020 Trust, in addition to Michael Hsing’s directly held shares of company common stock.

At what price were the 136,825 MPWR shares awarded to the CEO?

The 136,825 Monolithic Power Systems shares were awarded at a reported price of $0 per share. This reflects stock delivered through vested performance-based restricted stock units rather than an open-market purchase, and is subject to applicable tax withholdings under the grant agreement.