UCLA is #1 in CA for undergraduate business economics. I believe the other UC’s (i.e., Davis, etc.) are up there.
If you are just looking at pure undergraduate economics, Stanford is #1, UC Berkeley #2, UCLA #3…I am not sure if Cal Tech has an undergraduate economics program. If they do, I am sure it would be highly ranked and above UCLA.
UC Berkeley Haas is #1 in CA for undergraduate business schools. USC Marshall is #2 in CA. UCI, UCR are up there in the top 20 undergraduate business schools in CA.