STOCK TITAN

Monolithic Power (MPWR) EVP reports 30-share 10b5-1 insider sale

Filing Impact
(Neutral)
Filing Sentiment
(Negative)
Form Type
4

Rhea-AI Filing Summary

MONOLITHIC POWER SYSTEMS INC EVP Maurice Sciammas reported a small preplanned insider sale through a family trust. A trust named Clement Sciammas Trust sold 30 shares of common stock at $1,533.95 per share in an open-market transaction made pursuant to a Rule 10b5-1 trading plan adopted on 11/19/2025. Following this sale, that trust held 1,179 shares indirectly, while Sciammas also reported 166,644 shares held directly, suggesting this was a minor, routine disposition relative to his overall reported holdings.

Positive

  • None.

Negative

  • None.
Insider Sciammas Maurice
Role EVP, WW Sales & Marketing
Sold 30 shs ($46K)
Type Security Shares Price Value
Sale Common Stock 30 $1,533.95 $46K
holding Common Stock -- -- --
holding Common Stock -- -- --
holding Common Stock -- -- --
holding Common Stock -- -- --
holding Common Stock -- -- --
holding Common Stock -- -- --
holding Common Stock -- -- --
holding Common Stock -- -- --
holding Common Stock -- -- --
holding Common Stock -- -- --
holding Common Stock -- -- --
Holdings After Transaction: Common Stock — 1,179 shares (Indirect, Clement Sciammas Trust); Common Stock — 166,644 shares (Direct, null)
Footnotes (1)
  1. [object Object]
Shares sold 30 shares Open-market sale by Clement Sciammas Trust
Sale price per share $1,533.95/share Price for the 30 shares sold
Trust holdings after sale 1,179 shares Clement Sciammas Trust post-transaction balance
Direct holdings 166,644 shares Common stock held directly by Maurice Sciammas
Sell transactions 1 transaction transactionSummary sellCount
Net buy/sell shares -30 shares Net effect of reported buy and sell activity
Rule 10b5-1 trading plan regulatory
"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted on 11/19/2025."
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.
open-market sale financial
"transaction_action: "open-market sale" for the 30-share disposition"
An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.
indirect ownership financial
"direct_or_indirect: "I" and nature_of_ownership describing various trusts and accounts"
GRATs financial
"nature_of_ownership: "Various Sciammas GRATs" indicating grantor retained annuity trusts"
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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)
06/01/2026
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 Stock06/01/2026S30(1)D$1,533.951,179IClement Sciammas Trust
Common Stock166,644D
Common Stock1,699IThe Joseph Roger Sciammas 2020 Irrevocable Trust
Common Stock2,000IRosalind Sciammas Family 2021 Trust
Common Stock919IRosalind Sciammas Brokerage Account
Common Stock51,023ISciammas Family Trust
Common Stock12,625IVarious 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 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 11/19/2025.
Remarks:
/s/ Saria Tseng, attorney-in-fact for Mr. Maurice Sciammas06/03/2026
** 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)

FAQ

What insider transaction did MPWR executive Maurice Sciammas report on this Form 4?

Maurice Sciammas reported an indirect sale of 30 shares of Monolithic Power Systems common stock. The sale was executed by the Clement Sciammas Trust, an entity associated with him, and was disclosed as an open-market transaction under a pre-established Rule 10b5-1 trading plan.

At what price were the MPWR shares sold in Maurice Sciammas’s reported transaction?

The reported transaction shows 30 shares of Monolithic Power Systems common stock sold at $1,533.95 per share. This price reflects the average sale price for the disclosed open-market transaction executed by the Clement Sciammas Trust as part of the preplanned trading arrangement.

How many MPWR shares does the Clement Sciammas Trust hold after the reported sale?

After the sale, the Clement Sciammas Trust held 1,179 shares of Monolithic Power Systems common stock indirectly for Maurice Sciammas. This post-transaction balance indicates that only a small portion of the trust’s reported holdings was sold in this specific transaction.

What are Maurice Sciammas’s direct holdings of MPWR shares following this Form 4 filing?

Following the reported activity, Maurice Sciammas reported 166,644 shares of Monolithic Power Systems common stock held directly. This direct position is separate from his various indirect holdings through family trusts and related accounts disclosed in the same Form 4 filing.

Were Maurice Sciammas’s MPWR share sales made under a Rule 10b5-1 trading plan?

Yes. A footnote states the transaction was made pursuant to a Rule 10b5-1 trading plan adopted on 11/19/2025. Such plans allow pre-scheduled trades, indicating this sale was part of a structured program rather than a spontaneous market-timing decision.

What types of indirect MPWR share holdings does Maurice Sciammas report besides the selling trust?

Sciammas reports multiple indirect holdings in Monolithic Power Systems through entities such as the Sciammas Family Trust, various Sciammas GRATs, several 2020 and 2021 family trusts, and brokerage or family accounts, each holding specified amounts of common stock as of the reported date.