A list of Oklahoman companies. Many well known Oklahoma companies have been included. While this list isn't definitive, these are most of the top businesses in the state of Oklahoma. As a country, the United States has encouraged entrepreneurship throughout much of its history. The state of Oklahoma is no exception to this rule, and new businesses are started in Oklahoma 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 Oklahoma.