[Form 4] MONOLITHIC POWER SYSTEMS INC Insider Trading Activity

Rhea-AI Filing Summary

MONOLITHIC POWER SYSTEMS INC interim CFO Robert W. Dean II reported a non-market share transfer. On 2026-05-13, a Form 4 shows an "other" transaction moving 2,156 shares of common stock from his direct holdings.

The filing states no funds were exchanged, no sale occurred, and he no longer has any pecuniary interest in the transferred shares, indicating a non-cash disposition. After this restructuring, he reports 5,904 common shares held directly and 65 shares held indirectly under "Held by Parent & Daughter."

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider DEAN ROBERT W II

Role Interim CFO

Type	Security	Shares	Price	Value
Other	Common Stock	2,156	$0.00	--
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 5,904 shares (Direct, null); Common Stock — 65 shares (Indirect, Held by Parent & Daughter)

Footnotes (1)

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Key Figures

Restructuring transfer: 2,156 shares Transfer price: $0.0000 per share Direct holdings after: 5,904 shares +3 more

6 metrics

Restructuring transfer 2,156 shares Code J other transaction on May 13, 2026

Transfer price $0.0000 per share No funds exchanged for 2,156 transferred shares

Direct holdings after 5,904 shares Common stock held directly after restructuring

Indirect holdings after 65 shares Common stock held indirectly, Held by Parent & Daughter

Transaction code J Other acquisition or disposition, restructuring type

Restructuring shares 2,156 shares Classified as restructuring in transaction summary

Key Terms

pecuniary interest, transaction code J, indirect ownership, Form 4

4 terms

pecuniary interest financial

"the reporting person no longer retains any pecuniary interest in the shares"

transaction code J regulatory

"transaction_code_description": "Other acquisition or disposition""

indirect ownership financial

""direct_or_indirect": "I", "nature_of_ownership": "Held by Parent & Daughter""

Form 4 regulatory

"INSIDER FILING DATA (Form 4)"

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^*

DEAN ROBERT W II

(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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/13/2026

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	05/13/2026		J		2,156	D	$0(1)	5,904	D
Common Stock								65	I	Held by Parent & Daughter

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 transaction involved a transfer of securities from the reporting person's direct holdings to an individual who is not an immediate family member sharing the same household. No funds were exchanged and no sale of shares occurred in the transfer. Following the completion of the transfer, the reporting person no longer retains any pecuniary interest in the shares.

Remarks:

	/s/ Saria Tseng, attorney-in-fact for Mr. Robert W. Dean II	05/15/2026
	** 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)