Mr. Deming Xiao - 06 May 2026 Form 4 Insider Report for MONOLITHIC POWER SYSTEMS INC (MPWR)

Reporting relationship: EVP, Global Operations
Issuer ticker: MPWR
Reported as of: 06 May 2026
Net transaction value: -$49,636,560
SEC form: 4
Accepted by SEC: 08 May 2026, 18:15:19 UTC
Prior SEC filing: 10 Feb 2026
Source filing: View source filing
Reporting owner signature: /s/ Saria Tseng, attorney-in-fact for Mr. Deming Xiao

Key filing fact

Mr. Deming Xiao filed Form 4 for MONOLITHIC POWER SYSTEMS INC (MPWR) on 08 May 2026.

Key facts

This page summarizes Mr. Deming Xiao's Form 4 filing for MONOLITHIC POWER SYSTEMS INC (MPWR).
4 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 08 May 2026, 18:15.

Change

Previous filing in this sequence was filed on 10 Feb 2026.
Current net transaction value: -$49,636,560.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001308647 Primary reporting owner

Xiao Deming

Relationship: EVP, Global Operations
Address: 1555 PALM BEACH LAKES BLVD., WEST PALM BEACH
Signature: /s/ Saria Tseng, attorney-in-fact for Mr. Deming Xiao
Signature date: 08 May 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

MPWR transaction

Common Stock

Sale

Transaction value: $5,487,457
Shares: -3,329
Change %: -1.4%
Price: $1648.38
Shares after: 232,630
Date: 06 May 2026
Ownership: Direct
Footnotes: F1, F2

MPWR transaction

Common Stock

Sale

Transaction value: $23,415,218
Shares: -14,167
Change %: -6.1%
Price: $1652.80
Shares after: 218,463
Date: 06 May 2026
Ownership: Direct
Footnotes: F3

MPWR transaction

Common Stock

Sale

Transaction value: $19,227,014
Shares: -11,597
Change %: -5.3%
Price: $1657.93
Shares after: 206,866
Date: 06 May 2026
Ownership: Direct
Footnotes: F4

MPWR transaction

Common Stock

Sale

Transaction value: $1,506,872
Shares: -907
Change %: -0.44%
Price: $1661.38
Shares after: 205,959
Date: 06 May 2026
Ownership: Direct
Footnotes: F5

MPWR holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 20,455
Date: 06 May 2026
Ownership: by Spouse

MPWR holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 4,336
Date: 06 May 2026
Ownership: Christopher Chao Xiao Trust

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 5 footnotes

Footnote F1

Ending balance includes 27 shares acquired on February 17, 2026 through the Company's qualified ESPP program.

Footnote 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 $1,645.48 to $1,650.43. 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.

Footnote 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 $1,650.75 to $1,655.75. 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.

Footnote 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 $1,655.80 to $1,660.72. 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.

Footnote 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 $1,660.99 to $1,662 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.