Monolithic Power (MPWR) director sells 50 shares at $1,420 in reported trade

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

Director Chang Kuo Wei Herbert reported a sale of 50 shares of Monolithic Power Systems common stock on 2026-08-11 . The transaction was reported as a non-derivative open-market or private sale.

Q: At what price were the MPWR shares sold in this Form 4?

The 50 shares of MPWR common stock were sold at $1,420.00 per share . The transaction is categorized as a sale in an open market or private transaction, with the price reported on a per-share basis.

Q: How many MPWR shares does the reporting person hold after this transaction?

After the reported sale, the director holds 565 shares of Monolithic Power Systems common stock directly. This figure is disclosed as the total shares beneficially owned following the transaction on the Form 4.

Q: Was the MPWR insider sale made under a Rule 10b5-1 trading plan?

The filing’s Rule 10b5-1 checkbox is not checked , indicating the transaction is not affirmed as made under a Rule 10b5-1 trading plan. No additional footnote about a trading plan is provided.

Q: What type of security was involved in the MPWR Form 4 transaction?

The transaction involved Common Stock of Monolithic Power Systems. It is reported as a non-derivative security, meaning no options or other derivative instruments were exercised or converted in connection with this sale.

Filing Impact

(Neutral)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

Monolithic Power Systems, Inc. director Chang Kuo Wei Herbert reported selling 50 shares of common stock on 2026-08-11. The sale was a non-derivative transaction in the open market or a private transaction at a price of $1,420.00 per share, leaving him with 565 shares held directly.

Insider Trade Summary

Net Seller: 50 shares

Net Sell 1 txn

Insider CHANG KUO WEI HERBERT

Role Director

Sold 50 shs ($71K)

Type	Security	Shares	Price	Value
Sale	Common Stock	50	$1,420.00	$71K

Holdings After Transaction: Common Stock — 565 shares (Direct)

Key Figures

Shares sold: 50 shares Sale price per share: $1,420.00 per share Shares after transaction: 565 shares

3 metrics

Shares sold 50 shares Non-derivative sale of common stock on 2026-08-11

Sale price per share $1,420.00 per share Price reported for the 50-share sale of common stock

Shares after transaction 565 shares Total common shares beneficially owned following the sale

Key Terms

non-derivative, beneficially owned, open market or private transaction

3 terms

non-derivative financial

"The sale was a non-derivative transaction in common stock."

beneficially owned financial

"Total shares beneficially owned following the transaction is 565."

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

open market or private transaction financial

"Transaction code S indicates a sale in open market or private transaction."

FAQ

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

Director Chang Kuo Wei Herbert reported a sale of 50 shares of Monolithic Power Systems common stock on 2026-08-11. The transaction was reported as a non-derivative open-market or private sale.

At what price were the MPWR shares sold in this Form 4?

The 50 shares of MPWR common stock were sold at $1,420.00 per share. The transaction is categorized as a sale in an open market or private transaction, with the price reported on a per-share basis.

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

After the reported sale, the director holds 565 shares of Monolithic Power Systems common stock directly. This figure is disclosed as the total shares beneficially owned following the transaction on the Form 4.

Was the MPWR insider sale made under a Rule 10b5-1 trading plan?

The filing’s Rule 10b5-1 checkbox is not checked, indicating the transaction is not affirmed as made under a Rule 10b5-1 trading plan. No additional footnote about a trading plan is provided.

What type of security was involved in the MPWR Form 4 transaction?

The transaction involved Common Stock of Monolithic Power Systems. It is reported as a non-derivative security, meaning no options or other derivative instruments were exercised or converted in connection with this sale.

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 08/13/2026 - 05:24 PM Accepted by SEC EDGAR 08/13/2026 - 05:23 PM

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)
08/11/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	08/11/2026		S		50	D	$1,420	565	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

Remarks:

	/s/ Saria Tseng, attorney-in-fact for Mr. Herbert Chang	08/13/2026
	** 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)

Source: View Original Filing on SEC EDGAR