Lukas Walton

Lukas Walton is the grandson of Walmart founder Sam Walton.

He inherited his fortune when his father, John Walton, died in a 2005 plane crash.

He received about one-third of his father's estate; his mother, Christy Walton, got about one-sixth.

He owns stakes in Walmart, First Solar and Arvest Bank, though he does not work for the companies.

Walton has donated at least $149 million to his family's namesake foundation, where he chairs the environment program committee.