Wal-Mart heirs the Walton family see $11b wiped off their fortune in a day

A lower earnings outlook saw Wal-Mart shares tumble 10 per cent (Getty)

Wal-Mart customers, popping in to get their toilet roll and dog food, will not have noticed when the US chain announced that its yearly earnings would be 12 per cent less than expected on Wednesday.

But it had a catastrophic effect on the fortune of the Walton family, which controls more than half the shares of Wal-Mart. The four heirs are the children of Sam Walton: Jim, Rob and Alice, and Chrissy Walton, who inherited her stake from her husband John Walton.

"Watch out for falling prices": Bloomberg Billionaire's Index data shows the only way is down for the Walton Family

The lower earnings outlook saw Wal-Mart shares tumble 10 per cent, wiping a tenth off the value of the company, which has a market value in excess of $200 billion.

That wiped $11 billion off the combined wealth of the four Wal-Mart heirs, which amounts to more than $120 billion, according to Bloomberg. The family has lost an estimated $41 billion since the beginning of the year.

Warren Buffett, who also invests in Wal-Mart, has seen his personal fortune decline $12.1 billion in 2015.

Revenues are down at Wal-Mart as it struggles to catch up with Amazon in e-commerce. A rise in hourly wages and investment in training has also eaten into company profits.