Net worth: $35.1 billion

Age: 68

Country: US

Industry: Retail

Source of wealth: Inheritance; Walmart

James "Jim" Walton's parents, Helen and Sam Walton, purchased a controlling stake in Arkansas' Bank of Bentonville the year before opening the first Walmart store in Rogers, Arkansas, in 1962 — when Jim was just 14. Within five years, the family owned 24 of the retail stores and in 1972 listed Walmart on the New York Stock Exchange. In 1975, after working in Walmart's real-estate department for a few years, Jim joined his parents' bank, later renamed Arvest Bank Group. He's now chairman and CEO of the regional community bank, which has $15 billion in assets. Over the last year, Walton's has increased by $2.7 billion.

The businessman is also director of Walton Enterprises, the holding company for the Walton family assets, and chairman of Community Publishers, an Arkansas-based newspaper firm. After the death of his brother John in 2005, Jim joined the board of Walmart, where he serves as a director today.

While America's richest family remains incredibly private, the Walton Family Foundation, of which Jim is secretary and treasurer, has donated millions to charitable causes. In December 2015, Jim and his siblings donated $407 million worth of Walmart shares to a newly formed trust that funds the Walton's philanthropy, which focuses on educational, cultural, community development, and social causes.