Who wants to be a billionaire? More than 40 impoverished Chinese tycoons, who have lost their platinum status thanks to the world's financial turmoil.

Louis Vuitton, Cartier and Bentley should perhaps be bracing themselves for leaner times. The combined worth of the country's 400 richest people has plummeted by 40% to a mere $173bn (£100bn) since last year, new research has shown.

That has slashed the number of Chinese billionaires from 66 in 2007 to just 24. It would have been even lower without the yuan's rise against the dollar.

A 60% plunge in the Chinese stockmarket, and a 50% drop in Hong Kong shares, has wiped hundreds of millions of dollars off the biggest fortunes. The top 40 lost an even larger proportion - $68bn, or 57% - according to Forbes magazine, which compiles the annual rich list.

Yang Huiyuan, the property heiress who topped last year's list, is the biggest loser. Her net worth dropped a staggering $14bn, leaving her with $2.2bn - merely enough to scrape in at third place.

Property magnates dominated 2007's list. But the sales have slumped this year - wiping out 98% of Cheung Chung Kiu's fortune. Last year, the boss of the developer CC Land stood at number 26. Now he is outside the top 400.

"You can't really believe it," said Zhang Xin, who runs another well-known property firm, Soho China. She lost two-thirds of her fortune but clung on to billionaire status with her remaining $1.2bn. Yet, like many, she was optimistic about the future: "We'll ride with the next wave," she told Forbes.

Manufacturing businesses have also suffered, cutting the fortune of Yan Cheung to only $265m. The head of Nine Dragons Paper, China's largest packaging maker, was previously one of only 10 self-made female billionaires in the world.

And Larry Yung of Citic Pacific lost more than $500m in a single day. But Zhou Chengjian bucked the trend by climbing 351 places to fifth spot after his fashion firm boosted his wealth to $2bn.

More bad news may be on its way for the newly impecunious - yesterday the benchmark Shanghai composite index slid again.