Monolithic Power (NASDAQ: MPWR) director sells 50 shares

Rhea-AI Filing Summary

For MONOLITHIC POWER SYSTEMS, INC. (MPWR), director Chang Kuo Wei Herbert reported selling 50 shares of common stock on 2026-08-24 in a sale in open market or private transaction at $1,281.57 per share. After this transaction, he directly holds 515 shares of MPWR common stock.

Insider Trade Summary

Net Seller: 50 shares

Net Sell 1 txn

Insider CHANG KUO WEI HERBERT

Role Director

Sold 50 shs ($64K)

Type	Security	Shares	Price	Value
Sale	Common Stock	50	$1,281.57	$64K

Holdings After Transaction: Common Stock — 515 shares (Direct)

Key Figures

Shares sold: 50 shares Sale price per share: $1,281.57 per share Shares held after transaction: 515 shares

3 metrics

Shares sold 50 shares Common Stock sale on 2026-08-24

Sale price per share $1,281.57 per share Common Stock sale on 2026-08-24

Shares held after transaction 515 shares Direct ownership after 2026-08-24 sale

Key Terms

Form 4, sale in open market or private transaction, beneficial ownership

3 terms

Form 4 regulatory

"The Form 4 lists transaction code S and resulting holdings."

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

sale in open market or private transaction market

"Describes the transaction code S as a sale in open market or private transaction."

beneficial ownership regulatory

"The Form 4 structure reflects the reporting person’s beneficial ownership after the transaction."

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

FAQ

What insider transaction did MPWR director Chang Kuo Wei Herbert report?

He reported a sale of 50 MPWR common shares on 2026-08-24 in a sale in open market or private transaction at $1,281.57 per share, leaving him with 515 shares held directly.

At what price did the MPWR insider sell shares on 2026-08-24?

The MPWR director sold 50 common shares at a price of $1,281.57 per share in a transaction classified as a sale in open market or private transaction.

How many MPWR shares does the reporting person hold after this Form 4 transaction?

Following the reported transaction, the director directly holds 515 shares of MONOLITHIC POWER SYSTEMS, INC. common stock, as stated in the Form 4 data.

Was the MPWR insider transaction a purchase or a sale?

The reported MPWR insider transaction was a sale. The Form 4 lists transaction code S and describes it as a sale in open market or private transaction of 50 common shares.

Does the MPWR Form 4 indicate use of a Rule 10b5-1 trading plan?

The Form 4 data shows the Rule 10b5-1 checkbox flag as false, indicating the filing does not affirm that the reported sale was made pursuant to a Rule 10b5-1 trading plan.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/25/2026 - 07:14 PM Accepted by SEC EDGAR 08/25/2026 - 07:13 PM Learn about SEC filing dates

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^*

CHANG KUO WEI HERBERT

(Last) (First) (Middle)

1555 PALM BEACH LAKES BLVD.

(Street)

WEST PALM BEACH FLORIDA 33401

(City) (State) (Zip)

UNITED STATES

(Country)

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
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/24/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	08/24/2026		S		50	D	$1,281.57	515	D

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:

Remarks:

	/s/ Saria Tseng, attorney-in-fact for Mr. Herbert Chang	08/25/2026
	** 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.
* Form 4: SEC 1474 (03-26)