Deming Xiao - Aug 1, 2025 Form 4 Insider Report for MONOLITHIC POWER SYSTEMS INC (MPWR)

Signature
/s/ Saria Tseng, attorney-in-fact for Mr. Deming Xiao
Stock symbol
MPWR
Transactions as of
Aug 1, 2025
Transactions value $
-$31,199,220
Form type
4
Date filed
8/4/2025, 07:58 PM
Previous filing
Feb 12, 2025
Next filing
Aug 12, 2025

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Xiao Deming EVP, Global Operations 5808 LAKE WASHINGTON BLVD NE, KIRKLAND /s/ Saria Tseng, attorney-in-fact for Mr. Deming Xiao 2025-08-01 0001308647

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MPWR Common Stock Sale -$31.2M -40K -24.75% $780.00 122K Aug 1, 2025 Direct F1
holding MPWR Common Stock 20.5K Aug 1, 2025 by Spouse
holding MPWR Common Stock 3.39K Aug 1, 2025 Christopher Chao Xiao Trust
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

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).

Explanation of Responses:

Id Content
F1 Ending balance includes 27 shares acquired on February 17, 2025 through the Company's qualified ESPP program.