Monolithic Power Systems (NASDAQ: MPWR) CEO sells 54,923 shares for RSU taxes

Rhea-AI Filing Summary

Monolithic Power Systems CEO Michael Hsing reported a tax-related share sale. On 02/06/2026, he sold 54,923 shares of common stock at $1,171.1637 per share to cover taxes due upon the release of restricted stock units under the company’s equity incentive plan.

After this transaction, he held 988,234 shares directly. Additional indirect holdings were reported as 133,040 shares held by the M Hsing 04 Trust and 12,825 shares held by the ZH Family 2020 Trust.

Insights

Equity compensation and insider-transactions analyst

Large CEO sale is disclosed as tax-covering for RSU release.

The CEO of Monolithic Power Systems, Michael Hsing, sold 54,923 common shares at $1,171.1637 per share on February 6, 2026. A footnote states these sales were to cover taxes triggered by restricted stock units vesting under the company’s equity incentive plan.

After the sale, Hsing still directly held 988,234 shares, plus indirect positions of 133,040 shares via the M Hsing 04 Trust and 12,825 shares via the ZH Family 2020 Trust. Because the filing characterizes the sale as tax-related to equity compensation, it reads more as administrative than as a change in long-term ownership intent.

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

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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)
02/06/2026

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	02/06/2026		S		54,923(1)	D	$1,171.1637	988,234	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. The reported sales were to cover taxes upon the release of restricted stock units, as required by the Company's equity incentive plan.

Remarks:

	/s/ Saria Tseng, attorney-in-fact for Mr. Michael R. Hsing	02/10/2026
	** 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 CEO Michael Hsing report on February 6, 2026?

MPWR CEO Michael Hsing reported selling 54,923 shares of Monolithic Power Systems common stock on February 6, 2026. The shares were sold at $1,171.1637 each, according to the Form 4 insider filing with the Securities and Exchange Commission.

Why did the MPWR CEO sell 54,923 shares of Monolithic Power Systems stock?

The 54,923-share sale by MPWR CEO Michael Hsing was to cover taxes due upon the release of restricted stock units. A footnote explains this was required under Monolithic Power Systems’ equity incentive plan terms when the RSUs vested.

How many MPWR shares does CEO Michael Hsing own after the reported sale?

After the February 6, 2026 sale, CEO Michael Hsing directly owned 988,234 MPWR common shares. The filing also shows indirect holdings of 133,040 shares through the M Hsing 04 Trust and 12,825 shares through the ZH Family 2020 Trust.

Were any MPWR shares in the Form 4 held indirectly through trusts?

Yes. The Form 4 lists 133,040 MPWR common shares held indirectly by the M Hsing 04 Trust and 12,825 shares held indirectly by the ZH Family 2020 Trust. These positions are reported separately from CEO Michael Hsing’s directly owned 988,234 shares.

What role does Michael Hsing hold at Monolithic Power Systems (MPWR)?

Michael Hsing is both a director and the Chief Executive Officer of Monolithic Power Systems. The Form 4 insider filing identifies him as an officer with the title CEO and also notes his status as a director of the company.

Does the MPWR Form 4 suggest discretionary selling by the CEO?

The Form 4 states the reported sales were made to cover taxes due upon the release of restricted stock units under the equity incentive plan. This language characterizes the transaction as tax-related to compensation rather than purely discretionary selling of MPWR shares.