Alice Walton - Alice and Helen Walton are each worth $18B. They are heirs to the fortune of Sam Walton, founder of Wal Mart. Liliane Bettencourt of the L'Oreal fortune is worth $17.2B . Following these are Abigail Johnson ($12B - Fidelity) and Barbara Cox Anthony and Anne Cox Chambers (both $11.3B - COx Enterprises) Not knowing the intricacies of the pre-nuptual, Melinda Gates might also be considered the wealthiest woman.