THEODORE BLEGEN - 02 Sep 2025 Form 4 Insider Report for MONOLITHIC POWER SYSTEMS INC (MPWR)

Signature
/s/ Saria Tseng, attorney-in-fact for Mr. Bernie Blegen
Issuer symbol
MPWR
Transactions as of
02 Sep 2025
Net transactions value
-$2,443,032
Form type
4
Filing time
03 Sep 2025, 18:39:25 UTC
Previous filing
04 Aug 2025
Next filing
01 Oct 2025

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
BLEGEN THEODORE EVP and CFO 5808 LAKE WASHINGTON BLVD NE, KIRKLAND /s/ Saria Tseng, attorney-in-fact for Mr. Bernie Blegen 02 Sep 2025 0001415033

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MPWR Common Stock Sale $80,343 -100 -0.23% $803.43 43,839 02 Sep 2025 Direct F1
transaction MPWR Common Stock Sale $80,464 -100 -0.23% $804.64 43,739 02 Sep 2025 Direct F1
transaction MPWR Common Stock Sale $161,314 -200 -0.46% $806.57 43,539 02 Sep 2025 Direct F1, F2
transaction MPWR Common Stock Sale $80,853 -100 -0.23% $808.53 43,439 02 Sep 2025 Direct F1, F3
transaction MPWR Common Stock Sale $405,725 -500 -1.2% $811.45 42,939 02 Sep 2025 Direct F1, F4
transaction MPWR Common Stock Sale $81,284 -100 -0.23% $812.84 42,839 02 Sep 2025 Direct F1
transaction MPWR Common Stock Sale $81,309 -100 -0.23% $813.09 42,739 02 Sep 2025 Direct F1
transaction MPWR Common Stock Sale $162,950 -200 -0.47% $814.75 42,539 02 Sep 2025 Direct F1, F5
transaction MPWR Common Stock Sale $326,156 -400 -0.94% $815.39 42,139 02 Sep 2025 Direct F1, F6
transaction MPWR Common Stock Sale $468,654 -574 -1.4% $816.47 41,565 02 Sep 2025 Direct F1, F7
transaction MPWR Common Stock Sale $81,844 -100 -0.24% $818.44 41,465 02 Sep 2025 Direct F1
transaction MPWR Common Stock Sale $164,140 -200 -0.48% $820.70 41,265 02 Sep 2025 Direct F1, F8
transaction MPWR Common Stock Sale $164,350 -200 -0.48% $821.75 41,065 02 Sep 2025 Direct F1, F9
transaction MPWR Common Stock Sale $103,646 -126 -0.31% $822.59 40,939 02 Sep 2025 Direct F1, F10
holding MPWR Common Stock 5,331 02 Sep 2025 Irrevocable Trust FBO Theodore F. Blegen
holding MPWR Common Stock 5,331 02 Sep 2025 Irrevocable Trust FBO Sarah N. Blegen
* 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 These transactions were made pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on 2/26/2025.
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 $806.25 to $806.89. 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.
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 $808.38 to $808.63. 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.
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 $811.11 to $811.96. 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.
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 $814.61 to $814.88. 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.
F6 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 $815.10 to $815.74. 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.
F7 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 $816.20 to $816.76. 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.
F8 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 $820.50 to $820.88. 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.
F9 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 $821.64 to $821.86. 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.
F10 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 $822.31 to $822.72. 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.