Form 144: Robert Dean reports sale of 85 MPWR shares

Robert Dean filed a Form 144 reporting proposed sale activity in Common Stock.

Rhea-AI Filing Summary

Robert Dean filed a Form 144 reporting proposed sale activity in Common Stock. The filing lists a prior sale of 85 shares on 02/23/2026 for $101,787.00. The excerpt also references time-based restricted stock units dated 05/15/2026 and contains broker/contact information for Morgan Stanley Smith Barney LLC.

Insights

Corporate Governance Analyst

Form 144 shows a reported insider disposition and recent past sale.

The filing names Robert Dean as the reporting person and records a prior sale of $101,787.00 for 85 shares on 02/23/2026. It also lists time-based restricted stock units dated 05/15/2026.

Cash‑flow treatment and the proposed offering size are not specified in the provided excerpt; subsequent filings or broker confirmations may disclose sale timing and methods.

Key Figures

Prior sale shares: 85 shares Proceeds reported: $101,787.00 RSU award date: 05/15/2026 +1 more

4 metrics

Prior sale shares 85 shares sold on 02/23/2026

Proceeds reported $101,787.00 value for 85 shares on 02/23/2026

RSU award date 05/15/2026 time-based restricted stock units listed

Filing/contact date 05/18/2026 date shown in excerpt

Key Terms

Form 144, time-based restricted stock units, Securities To Be Sold

3 terms

Form 144 regulatory

"Filer Information | 144: Filer Information"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

time-based restricted stock units financial

"Common Stock | 05/15/2026 | Time-based restricted stock units"

Time-based restricted stock units are a form of employee compensation where individuals are granted company shares that are earned over a set period, often as a reward for staying with the company. These shares typically become fully owned and transferable only after passing specific time milestones, encouraging long-term commitment. For investors, they highlight a company's focus on employee retention and can influence future stock supply and company stability.

Securities To Be Sold regulatory

"144: Securities To Be Sold | Common Stock"

FAQ

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

What does Robert Dean's Form 144 for MPWR report?

It reports a proposed sale of Common Stock and lists a prior sale of 85 shares on 02/23/2026 for $101,787.00. The filing also references time-based restricted stock units dated 05/15/2026.

How many shares did Robert Dean sell in the past three months on MPWR?

The excerpt shows a past sale of 85 shares on 02/23/2026 with a reported value of $101,787.00. No other past-sale quantities are shown in the provided excerpt.

Are there restricted awards mentioned in the Form 144 for MPWR?

Yes; the filing lists time-based restricted stock units with an award date of 05/15/2026. The excerpt does not quantify units or specify vesting details.

Who is the broker listed on the Form 144 for MPWR transactions?

The broker/contact shown is Morgan Stanley Smith Barney LLC at 1 New York Plaza, 8th Floor, New York, NY. The excerpt provides this broker information alongside the securities listing.

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

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Accepted by SEC EDGAR 05/18/2026 - 08:18 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001445300
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	MONOLITHIC POWER SYSTEMS INC
SEC File Number	000-51026
Address of Issuer	1555 PALM BEACH LAKES BLVD. WEST PALM BEACH FLORIDA 33401
Phone	561-839-3999
Name of Person for Whose Account the Securities are To Be Sold	DEAN ROBERT W II
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common Stock	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	4	6253.12	49139853	05/18/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common Stock	05/15/2026	Time-based restricted stock units	Issuer			4	05/15/2026	N/A

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Robert Dean 1555 PALM BEACH LAKESBLVD. WEST PALM BEACH FL 98033	Common Stock	02/23/2026	85	101787.00

144: Remarks and Signature

Remarks
Date of Notice	05/18/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Robert Dean
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)