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Monolithic Power EVP sells 15,000 shares

Maurice Sciammas, EVP, WW Sales & Marketing of Monolithic Power Systems, reported selling 15,000 shares of common stock on July 15, 2026 in 18 transactions under a Rule 10b5-1 trading plan adopted on November 24, 2025.

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

Rhea-AI Filing Summary

Maurice Sciammas, EVP, WW Sales & Marketing of Monolithic Power Systems, reported selling 15,000 shares of common stock on July 15, 2026 in 18 transactions under a Rule 10b5-1 trading plan adopted on November 24, 2025. Footnotes state each line’s price is a weighted average of multiple trades, with underlying trade prices ranging from $1,311.45 to $1,406.04 per share. He also reports various indirect holdings through family trusts and related accounts.

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Insider Sciammas Maurice
Role EVP, WW Sales & Marketing
Sold 15,000 shs ($20.25M)
Type Security Shares Price Value
Sale Common Stock F1, F2 527 $1,314.03 $692K
Sale Common Stock F1, F3 274 $1,318.42 $361K
Sale Common Stock F1, F4 409 $1,323.93 $541K
Sale Common Stock F1, F5 464 $1,329.30 $617K
Sale Common Stock F1, F6 776 $1,334.59 $1.04M
Sale Common Stock F1, F7 1,460 $1,339.59 $1.96M
Sale Common Stock F1, F8 1,864 $1,344.16 $2.51M
Sale Common Stock F1, F9 1,506 $1,348.91 $2.03M
Sale Common Stock F1, F10 5,640 $1,352.95 $7.63M
Sale Common Stock F1, F11 50 $1,359.36 $68K
Sale Common Stock F1, F12 240 $1,369.18 $329K
Sale Common Stock F1, F13 472 $1,375.47 $649K
Sale Common Stock F1, F14 418 $1,378.73 $576K
Sale Common Stock F1, F15 410 $1,384.11 $567K
Sale Common Stock F1, F16 50 $1,388.19 $69K
Sale Common Stock F1, F17 213 $1,396.16 $297K
Sale Common Stock F1, F18 117 $1,400.45 $164K
Sale Common Stock F1, F19 110 $1,405.71 $155K
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Holdings After Transaction: Common Stock — 151,644 shares (Direct); Common Stock — 1,699 shares (Indirect, The Joseph Roger Sciammas 2020 Irrevocable Trust); Common Stock — 2,000 shares (Indirect, Rosalind Sciammas Family 2021 Trust); Common Stock — 919 shares (Indirect, Rosalind Sciammas Brokerage Account); Common Stock — 52,586 shares (Indirect, Sciammas Family Trust); Common Stock — 11,062 shares (Indirect, Various Sciammas GRATs); Common Stock — 1,699 shares (Indirect, The Patrick Francis Sciammas 2020 Irrevocable Trust); Common Stock — 4,015 shares (Indirect, By Sciammas Trust 2020); Common Stock — 1,000 shares (Indirect, Peter Rafferty and Eric Toothill 2021Trust); Common Stock — 1,699 shares (Indirect, The Chloe Liliane Sciammas 2020 Irrevocable Trust); Common Stock — 1,149 shares (Indirect, Clement Sciammas Trust); Common Stock — 5,000 shares (Indirect, Clement Sciammas Family 2021 Trust)
Footnotes (19)
  1. F1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted on 11/24/2025.
  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 $1,311.45 to $1,316.40 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 $1,316.56 to $1,321.56. 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 $1,321.72 to $1,326.11. 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. F5. 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 $1,326.94 to $1,331.90. 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. F6. 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 $1,331.95 to $1,336.95. 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.
  7. F7. 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 $1,336.97 to $1,341.96. 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. F8. 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 $1,341.99 to $1,346.96. 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. F9. 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 $1,347.09 to $1,352.00. 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. F10. 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 $1,352.13 to $1,357.03. 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. F11. 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 $1,357.88 to $1,362.57. 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. F12. 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 $1,366.15 to $1,371.04. 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. F13. 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 $1,371.23 to $1,376.20. 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. F14. 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 $1,376.51 to $1,381.11. 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. F15. 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 $1,381.79 to $1,386.22. 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. F16. 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 $1,388.18 to $1,388.22. 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.
  17. F17. 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 $1,393.94 to $1,398.92. 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.
  18. F18. 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 $1,398.97 to $1,400.85. 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.
  19. F19. 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 $1,404.25 to $1,406.04. 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.
Shares sold 15,000 shares Total common shares sold by Maurice Sciammas on July 15, 2026
Number of sale transactions 18 Distinct sale transactions of common stock reported for July 15, 2026
Lowest weighted-average transaction price $1,314.03 per share Lowest reported weighted-average sale price among the 18 transactions
Highest weighted-average transaction price $1,405.71 per share Highest reported weighted-average sale price among the 18 transactions
Underlying trade price range low $1,311.45 per share Lowest individual trade price noted in the footnote ranges
Underlying trade price range high $1,406.04 per share Highest individual trade price noted in the footnote ranges
Rule 10b5-1 plan adoption date 11/24/2025 Adoption date of the trading plan governing the reported sales
Indirect holding entries 11 Number of indirect ownership lines, including family trusts and related accounts
Rule 10b5-1 trading plan regulatory
"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted on 11/24/2025."
A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.
weighted average sale price financial
"The price is the weighted average sale price for the transactions reported on this line."
irrevocable trust financial
"The Chloe Liliane Sciammas 2020 Irrevocable Trust"
An irrevocable trust is a legal arrangement where an owner transfers assets into a separate entity managed by a trustee and gives up the power to modify or reclaim those assets. For investors it matters because putting stock or other holdings into such a trust can change who controls and benefits from the assets, affect taxes and creditor protection, and influence how easy it is to sell or value those holdings—like placing valuables in a locked safe overseen by someone else.
GRATs financial
"Various Sciammas GRATs"

FAQ

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

What insider sale did MPWR executive Maurice Sciammas report?
He reported selling 15,000 shares of Monolithic Power Systems common stock on July 15, 2026. The sales occurred in 18 separate transactions under a Rule 10b5-1 trading plan, with underlying trade prices between $1,311.45 and $1,406.04 per share.

Were Maurice Sciammas’s MPWR stock sales pre-planned?
Yes. The transactions were executed under a Rule 10b5-1 trading plan adopted on November 24, 2025. Such plans schedule trades in advance, helping separate an insider’s trading activity from any access to nonpublic information.

At what prices were MPWR shares sold in Sciammas’s Form 4?
The reported weighted-average sale prices per transaction range from $1,314.03 to $1,405.71 per share. Footnotes add that individual underlying trades spanned from $1,311.45 to $1,406.04 per share during the trading window.

Does Maurice Sciammas still hold MPWR shares after these sales?
Yes. The Form 4 shows continuing direct holdings after the reported sales, including a line reflecting 151,644 directly held shares following one transaction. It also lists multiple indirect holdings through various family trusts and a related brokerage account.

What indirect MPWR holdings does Sciammas report in this filing?
He reports indirect ownership of common stock through several family-related entities, including the Sciammas Family Trust, multiple 2020 irrevocable trusts, Various Sciammas GRATs, and a Rosalind Sciammas brokerage account. In total, there are 11 indirect holding entries.

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

Form 4 Insider Transactions: What Each Field Means →
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SEC Form 4
FORM 4UNITED 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).
X
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*
Sciammas Maurice
(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)
Director10% Owner
XOfficer (give title below)Other (specify below)
EVP, WW Sales & Marketing
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
07/15/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock07/15/2026S527(1)D$1,314.03(2)166,117D
Common Stock07/15/2026S274(1)D$1,318.42(3)165,843D
Common Stock07/15/2026S409(1)D$1,323.93(4)165,434D
Common Stock07/15/2026S464(1)D$1,329.3(5)164,970D
Common Stock07/15/2026S776(1)D$1,334.59(6)164,194D
Common Stock07/15/2026S1,460(1)D$1,339.59(7)162,734D
Common Stock07/15/2026S1,864(1)D$1,344.16(8)160,870D
Common Stock07/15/2026S1,506(1)D$1,348.91(9)159,364D
Common Stock07/15/2026S5,640(1)D$1,352.95(10)153,724D
Common Stock07/15/2026S50(1)D$1,359.36(11)153,674D
Common Stock07/15/2026S240(1)D$1,369.18(12)153,434D
Common Stock07/15/2026S472(1)D$1,375.47(13)152,962D
Common Stock07/15/2026S418(1)D$1,378.73(14)152,544D
Common Stock07/15/2026S410(1)D$1,384.11(15)152,134D
Common Stock07/15/2026S50(1)D$1,388.19(16)152,084D
Common Stock07/15/2026S213(1)D$1,396.16(17)151,871D
Common Stock07/15/2026S117(1)D$1,400.45(18)151,754D
Common Stock07/15/2026S110(1)D$1,405.71(19)151,644D
Common Stock1,699IThe Joseph Roger Sciammas 2020 Irrevocable Trust
Common Stock2,000IRosalind Sciammas Family 2021 Trust
Common Stock919IRosalind Sciammas Brokerage Account
Common Stock52,586ISciammas Family Trust
Common Stock11,062IVarious Sciammas GRATs
Common Stock1,699IThe Patrick Francis Sciammas 2020 Irrevocable Trust
Common Stock4,015IBy Sciammas Trust 2020
Common Stock1,000IPeter Rafferty and Eric Toothill 2021Trust
Common Stock1,699IThe Chloe Liliane Sciammas 2020 Irrevocable Trust
Common Stock1,149IClement Sciammas Trust
Common Stock5,000IClement Sciammas Family 2021 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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Explanation of Responses:
1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted on 11/24/2025.
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 $1,311.45 to $1,316.40 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 $1,316.56 to $1,321.56. 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 $1,321.72 to $1,326.11. 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 $1,326.94 to $1,331.90. 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 $1,331.95 to $1,336.95. 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.
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 $1,336.97 to $1,341.96. 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 $1,341.99 to $1,346.96. 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 $1,347.09 to $1,352.00. 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 $1,352.13 to $1,357.03. 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 $1,357.88 to $1,362.57. 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 $1,366.15 to $1,371.04. 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 $1,371.23 to $1,376.20. 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 $1,376.51 to $1,381.11. 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 $1,381.79 to $1,386.22. 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 $1,388.18 to $1,388.22. 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.
17. 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 $1,393.94 to $1,398.92. 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.
18. 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 $1,398.97 to $1,400.85. 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.
19. 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 $1,404.25 to $1,406.04. 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. Maurice Sciammas07/17/2026
** Signature of Reporting PersonDate
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)

Source: View Original Filing on SEC EDGAR

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