Martha MacMillan

Martha MacMillan is one of 14 billionaire heirs to Cargill, the world's biggest agriculture business and America's largest private company. Her great-great-grandfather, W.W. Cargill, founded the business as a single grain warehouse on the end of an Iowa railroad line in 1865.The family still owns roughly 90% of Cargill, which did $115 billion in 2018 sales across food, agriculture, financial and industrial divisions.The Cargill-MacMillan family collects an estimated 18% of net profits as dividends every year.