New York - The number of millionaires in the world jumped 9.2% to 12 million last year, in part because of simultaneous strength in the stock, bond and real estate markets, according to a study of the high-net-worth population.
The survey, released on Tuesday by RBC Wealth Management and Capgemini Financial Services, tracked high-net-worth people, whom it defined as those with more than $1m that they can invest.
North America was home to the highest number of millionaires - 3.7m. But the study projected that the Asia-Pacific region, which held the top spot in 2011, would reclaim it.
Part of the strength in North America came from rising equities markets - the Standard & Poor's 500 stock index gained 13% in 2012. North American investors put 37% of their money into stocks, a higher proportion than people in the Asia-Pacific region, where investors tend to be more conservative, the study said.
The amount of wealth held by the world's richest people also increased substantially, rising 10% to $46.2 trillion, well above the pre-economic crisis level of $40.7 trillion in 2007.
The study forecast high-net-worth wealth would increase 6.5% annually to $55.8 trillion by 2015, mainly because of growth in the Asia-Pacific region.
The survey found that 53% of wealthy US individuals would prefer to have a single firm handle their financial accounts.
However, a 2011 study from Boston-based research firm Aite Group showed more than half of high-net worth investors held their money in four or more financial institutions.
"Having one super-adviser would be preferred, but finding someone who can do that well is hard," said Aite analyst Sophie Schmitt.
The RBC-Capgemini survey polled more than 4 000 high-net-worth people globally in February and March, including 736 Americans.