John Mars (net worth: $30.1 billion)

Born in 1935 in Arlington, Virginia, John Mars shares ownership of Mars Inc., the world’s largest confectioner. The closely held, McLean, Virginia-based company makes candy (M&M’s, Snickers, Milky Way), chewing gum (Juicy Fruit, Orbit), pet chow (Pedigree, Whiskas), and packaged foods (Uncle Ben’s), and had revenue of $35 billion in 2015.