The number of billionaires in Hong Kong has plunged by more than 50 per cent in the past year as the superwealthy are hammered by the global economic downturn, a survey found.

There were 19 billionaires at the beginning of 2009 compared with 40 at the same time last year, the annual "rich list" compiled by Forbes Asia magazine found.

Hong Kong’s richest man, 80-year-old property tycoon Li Ka-shing, held on to his number one ranking, but saw his wealth tumble by more than half to $19.7 billion, the study found.

The Kwok family, owner of Sun Hung Kai Properties, remained second, but saw its net worth plummet 55 per cent to $13 billion.

In third place was Lee Shau Kee, 81, owner of Henderson Land, who saw his fortune fall from $17 billion to $11 billion.

The biggest loser, however, was Macau casino magnate Stanley Ho, 87, whose net worth nosedived 89 per cent to $1.2 billion, sending him crashing from fifth in last year’s list to 19th place.

One upside of the recession is that it has become a lot easier to get on the rich list with the minimum net worth to achieve a ranking falling from $1.2 billion last year to $590 million this year.

"Hong Kong’s openness has helped it thrive in good times," said Russell Flannery, a senior editor with Forbes. "Yet, today, when so many major economies in the world are in recession, it’s tough for Hong Kong to avoid taking a hit along with everyone else."

Hong Kong, which once boasted the largest per-capita number of Rolls Royce cars, is one of the world’s wealthiest — and most expensive — cities and is home to some of Asia’s richest tycoons.

These are also painful times for India’s tycoons.

A falling stock market, a weak rupee and slowing economic growth have shaved about 60 per cent off the wealth of India’s 40 richest people, it said in its annual compilation, with their net worth plunging to $169 billion from $427 billion a year ago.

India had 123,000 millionaires in 2007 and showed the fastest pace of expansion, a Merrill Lynch/Capgemini report said.

The reality is harsh for steel baron Lakshmi Mittal, chief of Arcelor Mittal, the world’s top steelmaker, who gave up his No. 1 position on the Forbes list because of crashing prices.

The new No. 1, Mukesh Ambani, chief of India’s top private company Reliance Industries, has a net worth of about $25.5 billion, Forbes estimates, down 58 per cent from last year.