George Kaiser

George Kaiser took over his family's Kaiser-Francis Oil Company in the 1960s.

Kaiser bought the Bank of Oklahoma in 1991 for $60 million; he owns about 54% of the publicly-traded bank.

He also owns LNG firm Excelerate Energy and stakes in several companies, including publicly traded fintech firm Alkami and the Oklahoma City Thunder.

In the 1930s, Kaiser's parents fled Nazi Germany and settled in Tulsa, Oklahoma.

Kaiser has paid out more than $1 billion from his George Kaiser Family Foundation, which focuses on early childhood education.