Danny Johnston/AP
- Rob Walton, the eldest of Walmart founder Sam Walton's children, is retiring after more than 40 years on the company's board.
- With a net worth of $79.8 billion, he's among the 20 richest people in the world.
- Here's a look at the billionaire Walmart heir's life and career.
Walmart billionaire Rob Walton is stepping down from the board of his family's company.