Microsoft Corp founder Bill Gates is the richest man again, overtaking investor Warren Buffett, as the global financial meltdown wiped out $2 trillion from the net worth of the world's billionaires, Forbes Magazine said.

The number of billionaires in the world fell by nearly a third to 793 in the past year, with large numbers dropping off the list in Russia, India and Turkey.

Saudi Arabia’s Prince Alwaleed bin Talal, chairman of Kingdom Holding Company, is among the top 25 billionaires.

Gates regained his title as the richest man in the world, with $40 billion after slipping to third last year when he was worth $58 billion. Buffett, last year's richest man, fell to second place with $37 billion, down from $62 billion. Mexican telecommunications tycoon Carlos Slim took third place with $35 billion, down from $60 billion.

Collectively, the top three billionaires lost $68 billion in the year to February 13, when Forbes took a snapshot of wealth around the world to compile its annual list of billionaires.

Chief executive of Forbes Magazines Steve Forbes said that, while few would shed a tear for the plight of a billionaire, it was bad for the economy when entrepreneurs were in trouble.

"Billionaires don't have to worry about their next meal, but if their wealth is declining and you're not creating numerous new billionaires, it means the rest of the world is not doing very well," he told reporters. "The typical billionaire is down at least one third on their net worth."    

The net worth of the world's billionaires fell from $4.4 trillion to $2.4 trillion, while the number of billionaires was down to 793 from 1,125.

"It's the first time since 2003 that we have lost billionaires, but we've never before lost anywhere near this number," said Luisa Kroll, senior editor of Forbes.

New York City replaced Moscow as home to the most billionaires, with 55. Russia, which saw the number of super- rich soar in recent years, suffered among the biggest shocks, with the number of billionaires down to 32 from 87.

Other developing countries that saw fast growth in previous years were hit hard as well, including Turkey, where the number of billionaires fell to 13 from 35, partly due to the collapse in the value of the lira currency, and India.

Indian businessman Anil Ambani, the biggest gainer on last year's list, was the biggest loser this time, with $32 billion wiped out over the last 12 months. Ranked sixth last year, he fell to 34 with an estimated wealth of $10.1 billion.

"India took a huge whack," Kroll said, noting that last year Indians held four of the top 10 spots and now only two, and the number of Indian billionaires more than halved to 24.

Of those who remained or returned to the list, 656 saw their net worth fall, 52 held even and only 44 managed to expand their wealth.

The only person in the top 20 who did not lose money was New York Mayor Michael Bloomberg, whose net worth was revised up to $16 billion from $11.5 billion because of a revaluation of his media company, Bloomberg LP, Forbes said. He is now the richest man in New York, jumping from 65 in the world to 17.

Forbes senior editor Matthew Miller said that, in the current climate, those who lost only 20 percent of their wealth were doing relatively well; for example members of the Walton family which founded discount retailer Wal-Mart Stores Inc.

"They lost $5 billion each, but Wal-Mart stock hasn't completely fallen off the cliff like everything else," he said.

Another discount retailer riding out the storm was Japan's Tadashi Yanai. His firm Fast Retailing, known for its Uniqlo stores, helped push him from 296th last year to 76th and raised his net wealth to $6 billion from $3.6 billion.

Others who managed to get richer were investors George Soros and Ronald Perelman, as well as short-seller John Paulson, who h