Inside Wealth

Inside the World of Migrant Millionaires

Sam Bassett | Riser | Getty Images

The wealthy have never been more global than they are today. And that doesn't just mean they spend winter break in St. Bart's and summers in Cannes.

The transcontinental rich own homes on three of four continents, have family members and companies spread around the world and rarely spend more than a month in one place. They are citizens of Richistan. And their numbers are growing.

A new study by RBC Wealth Management and The Economist Intelligence Unit looked at millionaires who live or work outside their country of birth – or spend more than half their time outside their home country. (Read more: 'Cliff' Would Knock Out 300,000 Millionaires)

It found that the 96 percent of them were self-made, meaning they didn't inherit their money. About a third were "professionals," like doctors and lawyers. Just under 20 percent were entrepreneurs, and the rest were executives of public companies, real-estate investors or private equity chiefs.

Of the migrant millionaires under 40, a larger number were entrepreneurs or real-estate investors.

When it comes to their reasons for roaming, most cite quality of life. Fully 88 percent said that quality of life was "very or moderately important " when deciding to move abroad. Family reasons ranked second, with 79 percent, followed by "political stability" and "infrastructure."

Surprisingly, "business interests" ranked a distant fifth – disproving the notion that the wealthy move mainly to globalize their companies. That was followed by educational opportunities and language.

Not surprisingly, the migrant millionaires have a more global outlook than other investors. One in five invest more than half their assets outside their home countries. Global equities are favored by 36 percent of the group, compared to only 25 percent for less mobile millionaires.

The Europeans and Asians in the group are the most global in their investing habits. Real estate is an especially popular asset class among the globe-trotting elite.

"Real-estate is tangible," said one of the survey respondents. High-net-worth individuals are familiar with capital markets, but to them it's still virtual." (Read more: A Big Leap for the GOP, a Small Step for Revenue)

The rise of the stateless-rich has added to concerns about philanthropy, and that the rich aren't as rooted in any one country to give.The majority give 5 percent of less to charity. Only 6 percent give more than 10 percent --and most of those are in North America. Europeans donate the least.

When it comes to causes, most donate to children's charities, health-care and education.