Monolithic Power Systems CFO reports 2,941-share stake

The reported position includes 1,206 restricted stock units that vest over time, subject to continued employment.

Rhea-AI Filing Summary

Monolithic Power Systems, Inc. (MPWR) reports that Chief Financial Officer Frank Anthony Balow III had a direct common-stock position of 2,941 shares as of October 27, 2026. The position includes an aggregate of 1,206 shares of restricted stock units that vest, subject to continued employment, in installments scheduled from November 22, 2026 through February 22, 2030.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Balow Frank Anthony III

Role Chief Financial Officer

Type	Security	Shares	Price	Value
holding	Common Stock F1	--	--	--

Holdings After Transaction: Common Stock — 2,941 shares (Direct)

Footnotes (1)

1. F1. Includes an aggregate of 1,206 shares of restricted stock units that vest, subject to continued employment, as follows: 104 shares on 11/22/2026; 121 shares on 1/1/2027; 104 shares on 2/22/2027; 121 shares on 4/1/2027; 102 shares on 5/22/2027; 121 shares on 7/1/2027; 106 shares on 8/22/2027; 121 shares on 10/1/2027; 102 shares on 11/22/2027; 106 shares on 2/22/2028; 16 shares on 5/22/2028; 18 shares on 8/22/2028; 16 shares on 11/22/2028; 18 shares on 2/22/2029; 7 shares on 5/22/2029; 8 shares on 8/22/2029; 7 shares on 11/22/2029; 8 shares on 2/22/2030.

Key Figures

Direct common-stock position: 2,941 shares Restricted stock units: 1,206 shares Scheduled vesting installment: 104 shares +1 more

4 metrics

Direct common-stock position 2,941 shares As of October 27, 2026; includes restricted stock units

Restricted stock units 1,206 shares Aggregate amount; vesting is subject to continued employment

Scheduled vesting installment 104 shares November 22, 2026

Scheduled vesting installment 8 shares February 22, 2030

Key Terms

restricted stock units, vest, continued employment

3 terms

restricted stock units financial

"1,206 shares of restricted stock units"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

vest financial

"vest, subject to continued employment"

A vest is the process by which an employee earns the right to receive certain benefits or ownership interests, such as stock or retirement funds, over time. It’s similar to earning a reward gradually, ensuring that the benefit becomes fully yours only after a set period or meeting specific conditions. This makes it important for investors because it determines when they can actually claim or use those benefits.

continued employment financial

"subject to continued employment"

Continued employment means that an individual remains in their current job without interruption. For investors, it signals stability and ongoing work that can affect company performance and future prospects. Like a steady heartbeat for a business, sustained employment helps ensure consistent operations and financial health.

FAQ

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

How many MPWR shares does CFO Frank Anthony Balow III report?

Chief Financial Officer Frank Anthony Balow III reported a direct position of 2,941 shares of common stock as of October 27, 2026. The position includes an aggregate of 1,206 shares of restricted stock units.

When do Frank Anthony Balow III’s MPWR restricted stock units vest?

The 1,206 restricted stock units vest in installments subject to continued employment. The listed schedule begins November 22, 2026, with 104 shares, and extends through February 22, 2030, with 8 shares.

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

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Available on EDGAR 10/29/2026 - 06:06 PM EDT Accepted by SEC EDGAR 10/29/2026 - 06:06 PM EDT Learn about SEC filing dates

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

Balow Frank Anthony III

(Last) (First) (Middle)

1555 PALM BEACH LAKES BLVD.

(Street)

WEST PALM BEACH FLORIDA 33401

(City) (State) (Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
10/27/2026

3. Issuer Name and Ticker or Trading Symbol
MONOLITHIC POWER SYSTEMS, INC. [ MPWR ]

3a. Foreign Trading Symbol

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

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

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

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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	2,941(1)	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Includes an aggregate of 1,206 shares of restricted stock units that vest, subject to continued employment, as follows: 104 shares on 11/22/2026; 121 shares on 1/1/2027; 104 shares on 2/22/2027; 121 shares on 4/1/2027; 102 shares on 5/22/2027; 121 shares on 7/1/2027; 106 shares on 8/22/2027; 121 shares on 10/1/2027; 102 shares on 11/22/2027; 106 shares on 2/22/2028; 16 shares on 5/22/2028; 18 shares on 8/22/2028; 16 shares on 11/22/2028; 18 shares on 2/22/2029; 7 shares on 5/22/2029; 8 shares on 8/22/2029; 7 shares on 11/22/2029; 8 shares on 2/22/2030.

Remarks:

	/s/ Saria Tseng, attorney-in-fact for Mr. Frank Anthony Balow III	10/29/2026
	** 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 5 (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 3: SEC 1473 (03-26)