Theodore Blegen - 02 Feb 2026 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 Feb 2026
Net transactions value
-$3,389,266
Form type
4
Filing time
04 Feb 2026, 10:10:11 UTC
Previous filing
06 Jan 2026
Next filing
05 Feb 2026

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
BLEGEN THEODORE EVP and CFO 1555 PALM BEACH LAKES BLVD., WEST PALM BEACH /s/ Saria Tseng, attorney-in-fact for Mr. Bernie Blegen 02 Feb 2026 0001415033

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MPWR Common Stock Sale $244,328 -220 -0.32% $1110.58 68,112 02 Feb 2026 Direct F1, F2
transaction MPWR Common Stock Sale $44,684 -40 -0.06% $1117.11 68,072 02 Feb 2026 Direct F1
transaction MPWR Common Stock Sale $89,662 -80 -0.12% $1120.77 67,992 02 Feb 2026 Direct F1
transaction MPWR Common Stock Sale $44,902 -40 -0.06% $1122.56 67,952 02 Feb 2026 Direct F1
transaction MPWR Common Stock Sale $225,316 -200 -0.29% $1126.58 67,752 02 Feb 2026 Direct F1, F3
transaction MPWR Common Stock Sale $90,191 -80 -0.12% $1127.39 67,672 02 Feb 2026 Direct F1, F4
transaction MPWR Common Stock Sale $270,823 -240 -0.35% $1128.43 67,432 02 Feb 2026 Direct F1, F5
transaction MPWR Common Stock Sale $271,027 -240 -0.36% $1129.28 67,192 02 Feb 2026 Direct F1, F6
transaction MPWR Common Stock Sale $361,754 -320 -0.48% $1130.48 66,872 02 Feb 2026 Direct F1, F7
transaction MPWR Common Stock Sale $224,077 -198 -0.3% $1131.70 66,674 02 Feb 2026 Direct F1, F8
transaction MPWR Common Stock Sale $364,720 -322 -0.48% $1132.67 66,352 02 Feb 2026 Direct F1, F9
transaction MPWR Common Stock Sale $429,585 -379 -0.57% $1133.47 65,973 02 Feb 2026 Direct F1, F10
transaction MPWR Common Stock Sale $273,393 -241 -0.37% $1134.41 65,732 02 Feb 2026 Direct F1, F11
transaction MPWR Common Stock Sale $136,259 -120 -0.18% $1135.49 65,612 02 Feb 2026 Direct F1, F12
transaction MPWR Common Stock Sale $136,362 -120 -0.18% $1136.35 65,492 02 Feb 2026 Direct F1, F13
transaction MPWR Common Stock Sale $91,025 -80 -0.12% $1137.81 65,412 02 Feb 2026 Direct F1
transaction MPWR Common Stock Sale $91,159 -80 -0.12% $1139.49 65,333 02 Feb 2026 Direct F1, F14, F15
holding MPWR Common Stock 5,331 02 Feb 2026 Irrevocable Trust FBO Sarah N. Blegen
holding MPWR Common Stock 5,331 02 Feb 2026 Irrevocable Trust FBO Theodore F. 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 $1,110.14 to $1,110.68. 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 $1,126.50 to $1,126.71. 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 $1,127.28 to $1,127.49. 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 $1,128.32 to $1,128.64. 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 $1,129.07 to $1,129.60. 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 $1,130.18 to $1,130.95. 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 $1,131.38 to $1,131.91. 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 $1,132.33 to $1,132.84. 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 $1,133.00 to $1,133.86. 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.
F11 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 $1,134.00 to $1,134.78. 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.
F12 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 $1,135.09 to $1,135.71. 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.
F13 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 $1,136.18 to $1,136.69. 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.
F14 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 $1,139.44 to $1,139.54. 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.
F15 Ending balance has been adjusted for a one share rounding difference.