Oklahoma is home to several prominent billionaires whose fortunes are largely rooted in the energy sector, retail, and corporate enterprise. Prominent billionaires residing in the state include Harold Hamm, the visionary founder and executive chairman of Continental Resources, who played a pivotal role in the American shale oil revolution. Other notable Oklahoman billionaires include retail entrepreneur David Green (founder of Hobby Lobby) and financial leader George Kaiser (head of Kaiser-Francis Oil and major stakeholder in BOK Financial), who maintain their primary bases in Oklahoma City and Tulsa.