Net worth: $35.4 billion

Age: 72

Country: US

Industry: Retail

Source of wealth: Inheritance; Walmart

Samuel Robson "Rob" Walton is the oldest son of Walmart founder Sam Walton. He started working at the iconic retail behemoth in 1969, holding positions from senior vice president to general counsel to chairman, a role he stepped down from in June 2015 after 23 years on the job. His son-in-law was named as his successor.

Regulatory filings on New Year's Eve revealed that Walton and his brother each gave away 1.5 million Walmart shares to the family charity, Walton Family Holdings Trust, while sister Alice gave away 3.7 million shares, for a total family donation of $407 million. It's an incredible amount, but it's also ultimately a drop in the bucket for the Waltons.

His wealth has increased by $3.3 billion in the past year.