Maxis is a subsidiary of Electronic Arts, as one of it's 4 major video game labels. It was originally founded in 1987 as Maxis Software, as an independent company, it later became simply known as Maxis. They are well known for The Sims Series and The SimCity Series.
Maxis was founded in 1987 by Will Wright and Jeff Braun to help publish SimCity on Home computers. Before then, there were very limited releases on the Commodore 64, due to a lack of publishers that were interested in porting the game, as the game didn't have a "win" or "lose". After the first SimCity, it had many sequels.