Monolithic Power interim CFO granted 1,359 shares

DEAN ROBERT W II reported acquisition or exercise transactions in this Form 4 filing.

Rhea-AI Filing Summary

DEAN ROBERT W II reported acquisition or exercise transactions in this Form 4 filing.

Monolithic Power Systems interim CFO Robert W. Dean II reported an equity award of 1,359 shares of common stock linked to market-based restricted stock units granted in 2023. The Compensation Committee certified achievement of the three-year performance goals on July 25, 2026, and the shares will vest in three equal annual installments from July 25, 2027 through July 25, 2029. Following this grant, Dean beneficially owns 7,237 shares directly and 65 shares indirectly held by a Parent & Daughter account.

Insider Trade Summary

Grant/Award: 1,359 shares

Grant/Award 2 txns

Insider DEAN ROBERT W II

Role Interim CFO

Type	Security	Shares	Price	Value
Grant/Award	Common Stock F1	1,359	$0.00	$0.00
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 7,237 shares (Direct); Common Stock — 65 shares (Indirect, Held by Parent & Daughter)

Footnotes (1)

1. F1. On July 25, 2023, the reporting person was granted market-based restricted stock units ("MSUs") subject to the achievement of stock price targets and relative total stockholder return percentile rank over a three-year performance period. On July 25, 2026, the Company's Compensation Committee of the Board of Directors certified and approved the achievement of the performance conditions for the MSUs, which resulted in an award of 1,359 shares to the reporting person. 1/3 of the shares will vest on July 25, 2027, 1/3 of the shares will vest on July 25, 2028, and 1/3 of the shares will vest on July 25, 2029, pursuant to the grant agreement.

Key Figures

Equity award: 1,359 shares of Common Stock Direct holdings after award: 7,237 shares Indirect holdings: 65 shares +3 more

6 metrics

Equity award 1,359 shares of Common Stock Awarded upon certification of MSU performance conditions on July 25, 2026

Direct holdings after award 7,237 shares Common Stock beneficially owned directly by the interim CFO following the reported transaction

Indirect holdings 65 shares Common Stock held indirectly in an account described as Held by Parent & Daughter

Grant date of MSUs July 25, 2023 Original grant date of market-based restricted stock units that produced the 1,359-share award

Performance certification date July 25, 2026 Date the Compensation Committee certified achievement of MSU performance conditions

Vesting period July 25, 2027–July 25, 2029 One-third of the awarded shares vest on each of these three annual dates

Key Terms

market-based restricted stock units, relative total stockholder return percentile rank, performance period

3 terms

market-based restricted stock units financial

"the reporting person was granted market-based restricted stock units ("MSUs")"

relative total stockholder return percentile rank financial

"subject to the achievement of stock price targets and relative total stockholder return"

performance period financial

"over a three-year performance period. On July 25, 2026, the Company's Compensation Committee"

The performance period is the specific time span over which an investment’s results, an employee’s targets, or a fund’s returns are measured and judged. It matters to investors because the length and start/end of that window determine which gains or losses count toward performance fees, bonus payouts, or benchmark comparisons—much like timing a race decides who wins, the chosen period can change whether results look strong or weak.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did MPWR interim CFO Robert W. Dean II report in this Form 4?

Interim CFO Robert W. Dean II reported an equity award of 1,359 shares of Monolithic Power Systems common stock. The award stems from market-based restricted stock units whose three-year performance goals were certified on July 25, 2026, and will vest over three future years.

How many Monolithic Power Systems (MPWR) shares does the interim CFO now hold?

After the reported award, Robert W. Dean II beneficially owns 7,237 shares directly of MPWR common stock. He also has an additional 65 shares held indirectly through an account noted as “Held by Parent & Daughter” in the filing.

What performance conditions were tied to the 1,359-share award for MPWR’s interim CFO?

The 1,359-share award is based on market-based restricted stock units (MSUs) granted in 2023. These MSUs were subject to stock price targets and relative total stockholder return percentile rank measured over a three-year performance period ending with certification on July 25, 2026.

What is the vesting schedule for the 1,359 MPWR shares awarded to the interim CFO?

The 1,359-share award will vest in three equal installments. According to the grant terms, one-third of the shares will vest on July 25, 2027, another third on July 25, 2028, and the final third on July 25, 2029, subject to the grant agreement.

Was the MPWR Form 4 transaction reported under a Rule 10b5-1 trading plan?

No. The Form 4 indicates the Rule 10b5-1 checkbox was not selected, meaning the MSU-related stock award was not reported as executed under a pre-arranged trading plan. It reflects certification of prior performance conditions and the resulting stock grant.

Did the MPWR interim CFO buy or sell any shares for cash in this Form 4?

No cash purchase or sale is reported. The filing shows an acquisition coded as “A”, representing a grant or award of 1,359 shares at a reported price of $0.00 per share, consistent with a compensation-related stock award rather than an open-market trade.

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

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Available on EDGAR 07/28/2026 - 06:42 PM Accepted by SEC EDGAR 07/28/2026 - 06:42 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^*

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)
07/25/2026

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	07/25/2026		A		1,359(1)	A	$0	7,237	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. On July 25, 2023, the reporting person was granted market-based restricted stock units ("MSUs") subject to the achievement of stock price targets and relative total stockholder return percentile rank over a three-year performance period. On July 25, 2026, the Company's Compensation Committee of the Board of Directors certified and approved the achievement of the performance conditions for the MSUs, which resulted in an award of 1,359 shares to the reporting person. 1/3 of the shares will vest on July 25, 2027, 1/3 of the shares will vest on July 25, 2028, and 1/3 of the shares will vest on July 25, 2029, pursuant to the grant agreement.

Remarks:

	/s/ Saria Tseng, attorney-in-fact for Mr. Robert W. Dean II	07/28/2026
	** 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)