4) Cargill-MacMillan family (Net worth: $45 billion)

There are 14 billionaires in the Cargill-MacMillan family. It is the family with most number of billionaires. The family owns 88 percent of Cargill, Inc., the largest private company in the US in terms of revenue. The company processes crops, sells food, sources ingredients, trades commodities and provides financial risk management.