A list of Californian companies. Many well known California companies have been included. While this list isn't definitive, these are most of the top businesses in the state of California. As a country, the United States has encouraged entrepreneurship throughout much of its history. The state of California is no exception to this rule, and new businesses are started in California daily, ranging from corporations to LLCs to partnerships to sole proprietorships. This list, however, is mostly focused on the largest corporations in the state of California.This list answers the question of "what companies are based in California?" There are a significant number of the world's largest corporations that are based in the Golden State. Many of the biggest technology companies are based here, including Google, Facebook and eBay amongst the most prominent.