NEW YORK - Singapore has the highest density of millionaires at 8.5 per cent of the population, according to a Boston Consulting Group study.

Switzerland is second, at 6.6 per cent, followed by Kuwait, at 5.1 per cent.

In fourth place is the United Arab Emirates, at 4.5 per cent, then the United States, at 3.5 per cent.

The number of millionaires worldwide shrank 17.8 per cent to nine million, as the global recession caused the first worldwide contraction in assets under management in nearly a decade.

Europe and North America were hardest hit in that regard, posting 22 per cent declines.

The US still boasts 3.9 million millionaires, the highest worldwide.

Wealth dropped 11.7 per cent to US$92.4 trillion (S$131.5 trillion), and a return to 2007 levels of wealth will take six years, said the study that examined assets overseen by the asset-management industry.

Also hit hard were offshore wealth centres like Switzerland and the Caribbean, where assets declined by 8 per cent to US$6.7 trillion last year from US$7.3 trillion in 2007.

Europe posted a slightly higher US$32.7 trillion of assets under management, edging out North America for the wealthiest region, though total wealth in the region dropped 5.8 per cent.

Latin America was the only region to report a gain in assets under management, posting a 3 per cent uptick from US$2.4 trillion in 2007 to US$2.5 trillion last year.