The number of millionaires worldwide grew by nearly 2 million last year and the group grew nearly 14 per cent richer, boosted by rising stock markets and improving economies, according to a study released on Wednesday.

The number of high net worth individuals, who have $1 million or more to invest, rose 15 per cent to 13.7 million in 2013, and their combined wealth rose to $52.62 trillion, marking five years of growth since the 2008 financial crisis, according to Capgemini and RBC Wealth Management's latest world wealth report.

While more millionaires call North America home than any other region, Asia-Pacific was a close second and is expected to overtake North America in 2014, led by surging wealth in Japan, where stock and real estate markets gained, and China, where economic growth adds millionaires at a fast clip every year.

The US had the most millionaires, at 4 million, followed by Japan with 2.3 million. Germany was third with 1.1 million, and China was fourth with 758,000. Those four countries were home to about 60 per cent of the world's wealthy.

The population of global millionaires included 128,300 "ultra" high net worth individuals, who have more than $30 million of assets to invest. This segment, while only 0.9 per cent of the wealthy population, holds 34.6 percent of the group's combined wealth.

Beyond the four countries with the most millionaires, other clusters of wealth growth stood out in 2013. Those included oil-rich Norway and Kuwait, the financial centers of Hong Kong and Singapore, and the emerging economic power houses of India, Russia and Taiwan, all of which added to the population of millionaires at a faster-than-average clip.

Europe and Latin America lagged, the report showed.

"It was the second-fastest growth in the population since 2000, and it does come back to 2013 in particular was a very positive year for financial markets," George Lewis, group head of wealth management and insurance at RBC, said on the sidelines of the Reuters Global Wealth Management Summit in New York.

The report was based on a survey of more than 4,500 high net worth individuals across 23 countries.

While banks and wealth management firms compete fiercely for the business of the growing population of millionaires, the survey showed the wealthy gave their money managers lower performance ratings than last year, down 4 percentage points to 63 per cent in early 2014.

They have also taken a more global mindset in early 2014 than last year, allocating 37 per cent of their assets outside of their home region, up from 25 per cent the prior year. But cash levels remain high, at 27 per cent, suggesting a lingering caution after market losses five years ago - and a big reserve for investing when the time is right.

"It indicates a long memory from 2008 and 2009," Lewis said. "But it also allows individuals to have some flexibility to ... be opportunistic when it comes to new asset acquisition," he added.-Reuters