Director at Monolithic Power (MPWR) sells 486 shares in open market

Rhea-AI Filing Summary

Monolithic Power Systems director Jeff Zhou sold 486 shares of Common Stock in an open-market sale at $1,680 per share. This transaction reduced his direct holdings to 3,800 shares after the sale, indicating a partial, not complete, trim of his position.

Insider Trade Summary

Net Seller: 486 shares ($816,480)

Net Sell 1 txn

Insider Zhou Jeff

Role null

Sold 486 shs ($816K)

Type	Security	Shares	Price	Value
Sale	Common Stock	486	$1,680.00	$816K

Holdings After Transaction: Common Stock — 3,800 shares (Direct, null)

Footnotes (1)

Key Figures

Shares sold: 486 shares Sale price: $1,680.00 per share Shares held after: 3,800 shares +1 more

4 metrics

Shares sold 486 shares Open-market sale of Common Stock

Sale price $1,680.00 per share Price for the 486 sold shares

Shares held after 3,800 shares Direct ownership following the sale

Net shares sold 486 shares Net-sell direction in transaction summary

Key Terms

Common Stock, open-market sale, Form 4

3 terms

Common Stock financial

"Jeff Zhou sold 486 shares of Monolithic Power Systems Common Stock"

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

open-market sale financial

"The transaction was an open-market sale at $1,680 per share"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Form 4 regulatory

"The transaction details were disclosed on a Form 4 filing"

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.

Form 4 Insider Transactions: What Each Field Means →

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^*

Zhou Jeff

(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)
05/26/2026

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	05/26/2026		S		486	D	$1,680	3,800	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. Jeff Zhou	05/27/2026
	** 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)

FAQ

What insider transaction did MPWR director Jeff Zhou report?

Jeff Zhou reported selling 486 shares of Monolithic Power Systems Common Stock. The transaction was an open-market sale disclosed on a Form 4 filing, reflecting a partial reduction of his direct equity position in the company.

How many MPWR shares did Jeff Zhou sell and at what price?

Jeff Zhou sold 486 shares of Monolithic Power Systems at $1,680 per share. This was an open-market sale of Common Stock, representing a single reported transaction in the filing’s non-derivative securities section.

How many Monolithic Power Systems (MPWR) shares does Jeff Zhou hold after the sale?

After the transaction, Jeff Zhou directly holds 3,800 shares of Monolithic Power Systems Common Stock. This figure reflects his remaining position following the reported sale of 486 shares in the open market.

Was Jeff Zhou’s MPWR transaction an open-market trade?

Yes, the Form 4 describes Jeff Zhou’s transaction as an open-market sale. The filing uses transaction code “S” and labels the activity as a sale in the open market or a private transaction for Common Stock shares.

Does the MPWR Form 4 show any option exercises or derivative trades?

No, the Form 4 only reports a non-derivative Common Stock sale. The derivative summary section is empty, indicating no option exercises, warrant conversions, or other derivative transactions in this particular filing.