The Bass Family
Sid Richardson was a Texan oil tycoon between 1930s -1950s. After his death, his four nephews inherited the wealth as he had no heirs and had never married. Robert, Sid, Lee, and Edward Bass made wise investments and adopted a diversification strategy which included selling the oil assets in 2017 to ExxonMobil for $5.6 billion. With the injection of new funds, the fortune increased to about $13 billion.