Worked in Tech in Los Angeles since 2000. Although lesser known as "tech" companies, there are several companies that have large investments in serious technology in LA:
Disney NBCU (specifically Fandango, parts of former M-Go) Ticketmaster/Live Nation eHarmony Edmunds.com The Honest Company
Other Tech companies left off the list: Hulu Yahoo (much smaller than before) AOL Hyperloop One and Faraday Future are coming up