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  4. [Form 4] MONOLITHIC POWER SYSTEMS INC Insider Trading Activity

Monolithic Power CEO reports insider sale; holdings updated

Filing Impact
(Very High)
Filing Sentiment
(Very Negative)
Form Type
4

Rhea-AI Filing Summary

Monolithic Power Systems (MPWR) CEO and director Michael R. Hsing reported open-market sales of 40,000 shares of common stock on 11/11/2025 across multiple transactions. The filing lists weighted-average prices for each tranche, with disclosed price ranges from $952.05 to $967.17 for the respective trades. Following these sales, Hsing directly holds 955,669 shares.

The filing also shows indirect holdings of 133,040 shares by the M Hsing 04 Trust and 12,825 shares by the ZH Family 2020 Trust.

Positive

  • None.

Negative

  • None.
Insider Hsing Michael
Role CEO
Sold 40,000 shs ($38.34M)
Type Security Shares Price Value
Sale Common Stock 80 $951.69 $76K
Sale Common Stock 1,516 $952.62 $1.44M
Sale Common Stock 2,927 $953.69 $2.79M
Sale Common Stock 7,934 $954.61 $7.57M
Sale Common Stock 4,056 $955.46 $3.88M
Sale Common Stock 797 $956.50 $762K
Sale Common Stock 1,020 $957.71 $977K
Sale Common Stock 2,500 $958.59 $2.40M
Sale Common Stock 4,010 $959.45 $3.85M
Sale Common Stock 2,734 $960.45 $2.63M
Sale Common Stock 3,900 $961.47 $3.75M
Sale Common Stock 4,172 $962.57 $4.02M
Sale Common Stock 1,894 $963.41 $1.82M
Sale Common Stock 739 $964.38 $713K
Sale Common Stock 321 $965.44 $310K
Sale Common Stock 1,246 $966.30 $1.20M
Sale Common Stock 154 $967.15 $149K
holding Common Stock -- -- --
holding Common Stock -- -- --
Holdings After Transaction: Common Stock — 995,589 shares (Direct); Common Stock — 133,040 shares (Indirect, by M Hsing 04 Trust)
Footnotes (1)
  1. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $952.05 to $952.98. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $953.14 to $953.99. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $954.00 to $954.98. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $955.13 to $955.93. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $956.00 to $956.98. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $957.00 to $957.99. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $958.13 to $958.99. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $959.00 to $959.95. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $960.00 to $960.99. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $961.00 to $961.95. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $962.00 to $962.97. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $963.08 to $963.99. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $964.00 to $964.77. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $965.36 to $965.63. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $966.06 to $966.80. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $967.14 to $967.17. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
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*
Hsing Michael
(Last) (First) (Middle)
1555 PALM BEACH LAKES BLVD.
(Street)
WEST PALM BEACH FL 33401
(City) (State) (Zip)
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
X Officer (give title below) Other (specify below)
CEO
3. Date of Earliest Transaction (Month/Day/Year)
11/11/2025
4. If Amendment, Date of Original Filed (Month/Day/Year)
 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 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 11/11/2025 S 80 D $951.69 995,589 D
Common Stock 11/11/2025 S 1,516 D $952.62(1) 994,073 D
Common Stock 11/11/2025 S 2,927 D $953.69(2) 991,146 D
Common Stock 11/11/2025 S 7,934 D $954.61(3) 983,212 D
Common Stock 11/11/2025 S 4,056 D $955.46(4) 979,156 D
Common Stock 11/11/2025 S 797 D $956.5(5) 978,359 D
Common Stock 11/11/2025 S 1,020 D $957.71(6) 977,339 D
Common Stock 11/11/2025 S 2,500 D $958.59(7) 974,839 D
Common Stock 11/11/2025 S 4,010 D $959.45(8) 970,829 D
Common Stock 11/11/2025 S 2,734 D $960.45(9) 968,095 D
Common Stock 11/11/2025 S 3,900 D $961.47(10) 964,195 D
Common Stock 11/11/2025 S 4,172 D $962.57(11) 960,023 D
Common Stock 11/11/2025 S 1,894 D $963.41(12) 958,129 D
Common Stock 11/11/2025 S 739 D $964.38(13) 957,390 D
Common Stock 11/11/2025 S 321 D $965.44(14) 957,069 D
Common Stock 11/11/2025 S 1,246 D $966.3(15) 955,823 D
Common Stock 11/11/2025 S 154 D $967.15(16) 955,669 D
Common Stock 133,040 I by M Hsing 04 Trust
Common Stock 12,825 I ZH Family 2020 Trust
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 price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $952.05 to $952.98. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
2. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $953.14 to $953.99. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
3. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $954.00 to $954.98. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
4. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $955.13 to $955.93. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
5. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $956.00 to $956.98. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
6. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $957.00 to $957.99. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
7. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $958.13 to $958.99. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
8. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $959.00 to $959.95. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
9. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $960.00 to $960.99. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
10. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $961.00 to $961.95. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
11. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $962.00 to $962.97. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
12. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $963.08 to $963.99. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
13. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $964.00 to $964.77. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
14. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $965.36 to $965.63. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
15. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $966.06 to $966.80. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
16. The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $967.14 to $967.17. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
Remarks:
/s/ Saria Tseng, attorney-in-fact for Mr. Michael R. Hsing 11/11/2025
** 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.

Source: View Original Filing on SEC EDGAR

FAQ

How many MPWR shares did the CEO sell on 11/11/2025?

The CEO reported selling 40,000 shares of common stock across multiple transactions.

What is the CEO’s direct MPWR share ownership after the sales?

Direct beneficial ownership is 955,669 shares following the reported transactions.

What were the price ranges for the MPWR share sales?

Disclosed trade ranges span from $952.05 to $967.17, based on weighted-average tranches.

Does the filing show any indirect MPWR holdings for the CEO?

Yes. Indirect holdings include 133,040 shares by the M Hsing 04 Trust and 12,825 shares by the ZH Family 2020 Trust.

What form was filed for these insider transactions for MPWR?

A Form 4 reporting changes in beneficial ownership was filed.

What is the CEO’s role at MPWR noted in the filing?

The reporting person is identified as a Director and Officer (CEO).