Zuckerberg bucks trend on rich list

Mark Zuckerberg became the world's fourth-richest person on Tuesday, as Facebook shares fended off plunging stock markets. The 31-year-old had a $50-bn fortune by the close of regular trading in New York. That vaulted him above America Movil SAB's Carlos Slim and Amazon's Jeff Bezos on the Bloomberg Billionaires Index, a daily ranking of the world's 400 richest people.

Zuckerberg is the only billionaire among the world's five-richest people whose fortune has increased this year. Half of the 10 wealthiest billionaires on Earth have made their fortunes in technology. Here is a look at the top five on the net worth list and the change in net worth from the previous day: