Saria Tseng - Sep 18, 2025 Form 4 Insider Report for MONOLITHIC POWER SYSTEMS INC (MPWR)

Signature
/s/ Saria Tseng
Stock symbol
MPWR
Transactions as of
Sep 18, 2025
Transactions value $
-$13,268,670
Form type
4
Date filed
9/23/2025, 02:35 PM
Previous filing
Feb 12, 2025
Next filing
Oct 17, 2025

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Tseng Saria EVP & General Counsel 5808 LAKE WASHINGTON BLVD NE, KIRKLAND /s/ Saria Tseng 2025-09-18 0001312593

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MPWR Common Stock Sale -$13.3M -14.5K -9.13% $914.45 144K Sep 18, 2025 Direct F1, F2
* 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 This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on 8/30/2024.
F2 Ending balance includes 27 shares acquired on February 17, 2025 through the Company's qualified ESPP program.