144 0001560945 XXXXXXXX LIVE 0001280452 MONOLITHIC POWER SYSTEMS INC 000-51026 1555 PALM BEACH LAKES BLVD. WEST PALM BEACH FL 33401 561-839-3999 Elmiger Eugen J Director Common Stock Luzerner Kantonalbank AG

Pilatusstrasse 12 Luzern V8 6003

12000 19828200.00 49135998 05/07/2026 NASDAQ Common Stock 10/23/2012 Restricted Stock Units Issuer N 1235 10/23/2012 N/A Common Stock 02/11/2014 Restricted Stock Units Issuer N 3493 02/11/2014 N/A Common Stock 02/09/2015 Restricted Stock Units Issuer N 2553 02/09/2015 N/A Common Stock 04/28/2016 Restricted Stock Units Issuer N 2181 04/28/2016 N/A Common Stock 02/07/2017 Restricted Stock Units Issuer N 1566 02/07/2017 N/A Common Stock 02/07/2018 Restricted Stock Units Issuer N 972 02/07/2018 N/A Y 05/06/2026 /s/ Eugen Elmiger