AMERICAN retailer Wal-Mart is on track to earn more than £150bn this financial year, unseating oil conglomerate ExxonMobil as the world's biggest corporation.

"Everyone needs toilet paper and toothpaste, and they are the most efficient at selling it," said Eric Beder, a retail analyst in New York.

Forty years ago, Sam Walton opened his first shop in Arkansas. Now, the chain, which in Britain owns Asda, has 4,150 shops around the world, selling everything from children's clothing to hunting equipment.

The Walton family is the richest in the world and five members are in the Forbes top ten wealthiest league.