The latest annual survey by Forbes magazine has shown that the global economic crisis has led to a sharp drop in the number of billionaires.
The survey said there were now a third fewer billionaires worldwide.
The magazine's editor-in-chief Steve Forbes said the super-rich in developing nations have been more affected by the financial meltdown than their counterparts in the West.
US tycoons are back on top with Microsoft founder Bill Gates again the world's richest man.
The wealthy few did not escape big shocks this year, with net worth on the list of 793 billionaires - down from 1,125 billionaires in 2008 - plummeting to $2.4 trillion (€1.88 trillion) from $4.4 trillion (€3.45 trillion).
The annual rich list put Mr Gates back on top with a net worth of $40bn (€31.33bn), although he saw his bank balance lose $18bn (€14.1bn) over the last 12 months.
In second came investor Warren Buffett with $37bn (€28.9bn), despite losing $25bn (€19.59bn) this year in the value of his Berkshire Hathaway shares.
Also losing $25bn (€19.59bn), Mexican telecoms king Carlos Slim still managed to come in third with $35bn (€27.42bn).
The US surge sent billionaires from India, Russia and Turkey into retreat.
Wealthy Americans fill ten of the 20 top spots and New York replaced Moscow as home to most billionaires, with 55 to 27. London comes in second with 28.
Russia, where wealth is closely tied to commodity prices, lost two thirds of its billionaires, down to 32.
Two Indians appear in the top 20, but not one from Russia, which had four in the previous year's list.
