10. (211) Valerie Mars, $7.62 billion
One of four sisters who share a spot on the billionaire index, Valerie Mars is senior vice president and head of corporate development at her family's candy and food conglomerate, where she started working in 1992. She graduated from Yale University and received her MBA from Columbia Business School. She sits on the board of directors of Fiat Chrysler Automobiles N.V. According to her biography on the car company's website, she serves on the Board of Conservation International and is a director emeritus of The Open Space Institute.