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  4. [Form 4] Monolithic Power Systems, Inc. Insider Trading Activity

Monolithic Power (MPWR) Director Disposes of 4,000 Shares; Beneficial Ownership Falls to 17,213

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

Rhea-AI Filing Summary

Monolithic Power Systems (MPWR) director Eugen J. Elmiger reported multiple open-market sales of common stock on 08/29/2025. The Form 4 lists six sale transactions totaling 4,000 shares executed at weighted-average prices ranging roughly from $844.00 to $849.41. After the reported sales the filing shows the reporting person beneficially owned 17,213 shares. The transactions were signed by an attorney-in-fact and the filing includes explanations that each line reflects a weighted-average sale price with price ranges available on request.

Positive

  • None.

Negative

  • Director sold 4,000 shares in open-market transactions on 08/29/2025, reducing his reported beneficial ownership to 17,213 shares.
  • Sales executed at high prices (weighted-average ranges approximately $844.00–$849.41), which may be interpreted by some investors as insider liquidity rather than new investment.

Insights

TL;DR: Director sold 4,000 MPWR shares at roughly $844–$849, reducing holdings to 17,213 shares; this is a routine insider sale, not a disclosed strategic change.

The filing documents open-market dispositions by a company director rather than option exercises or derivative activity. Total shares sold are clearly stated as 4,000 across six transactions with weighted-average prices provided and ranges disclosed for each line. Absent other company disclosures, these sales represent liquidity events by the reporting person and do not, on their face, indicate corporate-level developments such as governance changes, material contracts, or financial restatements. Investors may note the size of the holding post-sale (17,213 shares) when assessing insider alignment, but the Form 4 itself contains no operational or financial performance details.

TL;DR: Insider sales by a director are recorded and properly disclosed; the filing includes standard weighted-average price explanations.

The Form 4 appears procedurally complete: it identifies the reporting person as a director, lists transaction codes as sales, provides the dates, amounts, and weighted-average prices, and includes explanatory notes about price ranges and availability of per-price details. The signature is by an attorney-in-fact with a date. From a governance and compliance perspective, the submission meets disclosure requirements; it does not reveal any related-party transaction or change in board status.

Insider Elmiger Eugen J
Role Director
Sold 4,000 shs ($3.39M)
Type Security Shares Price Value
Sale Common Stock 800 $844.25 $675K
Sale Common Stock 700 $845.54 $592K
Sale Common Stock 700 $846.66 $593K
Sale Common Stock 900 $847.30 $763K
Sale Common Stock 100 $848.03 $85K
Sale Common Stock 800 $849.41 $680K
Holdings After Transaction: Common Stock — 17,213 shares (Direct)
Footnotes (4)
  1. F1. 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 $844.00 to $844.62. 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. F2. 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 $845.15 to $845.72. 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. F3. 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 $846.16 to $846.97. 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.
  4. F4. 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 $847.19 to $847.44. 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.

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Form 4 Insider Transactions: What Each Field Means →

FAQ

What insider activity did MPWR report on 08/29/2025?
Director Eugen J. Elmiger reported six open-market sales totaling 4,000 shares of Monolithic Power Systems common stock on 08/29/2025.

At what prices were the MPWR shares sold by the director?
The Form 4 shows weighted-average sale prices per line with ranges; overall prices reported span roughly $844.00 to $849.41.

How many MPWR shares did the reporting person own after the sales?
Following the reported transactions the filing shows the reporting person beneficially owned 17,213 shares.

Who signed the Form 4 for Eugen J. Elmiger?
The Form 4 was signed by /s/ Saria Tseng, attorney-in-fact for Mr. Eugen J. Elmiger on 08/29/2025.

Does the Form 4 indicate any derivative or option transactions?
No. Table II for derivative securities contains no reported acquisitions or dispositions; only non-derivative common stock sales are reported.
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*
Elmiger Eugen J
(Last) (First) (Middle)
5808 LAKE WASHINGTON BLVD NE
(Street)
KIRKLAND WA 98033
(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
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
08/29/2025
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 08/29/2025 S 800 D $844.25(1) 20,413 D
Common Stock 08/29/2025 S 700 D $845.54(2) 19,713 D
Common Stock 08/29/2025 S 700 D $846.66(3) 19,013 D
Common Stock 08/29/2025 S 900 D $847.3(4) 18,113 D
Common Stock 08/29/2025 S 100 D $848.03 18,013 D
Common Stock 08/29/2025 S 800 D $849.41 17,213 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:
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 $844.00 to $844.62. 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 $845.15 to $845.72. 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 $846.16 to $846.97. 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.
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 $847.19 to $847.44. 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. Eugen J. Elmiger 08/29/2025
** 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