George Kaiser

A family oil business provided the starting platform

Kaiser's family fled Nazi Germany and settled in Tulsa, where his father built an oil prospecting business. Kaiser later returned from Harvard and took over Kaiser-Francis Oil in 1969, inheriting a real operating platform but one far smaller than the fortune he ultimately created. ^[2][1]

The George Kaiser Family Foundation says the oil company had roughly a dozen local workers when Kaiser assumed control and later grew into an international energy exploration business with more than 1,000 employees. That expansion turned an inherited enterprise into a much more valuable energy asset. ^[2]

Kaiser added a second major wealth engine in 1991 when he bought Bank of Oklahoma out of federal receivership for about $60 million. Forbes says he now owns a majority of publicly traded BOK Financial, giving his fortune a large transparent banking component alongside private energy holdings. ^[1][2]

Energy and banking ownership continued to compound

Forbes also identifies large ownership positions in Excelerate Energy and other businesses, showing how Kaiser used the cash flow and capital base created by oil and banking to build a broader portfolio rather than relying on a single inherited asset. ^[1]

His path is therefore mixed: the family oil company supplied meaningful inherited capital and industry access, while decades of operating expansion, distressed bank acquisition and later investments created most of the eventual scale. The relevant personal wealth is his ownership in those businesses, not their gross assets or revenues. ^[1][2]