Millionaires are multiplying in the world's fastest-growing economies, leading to a potential boon for banks that manage money for the wealthy, according to a report by the Boston Consulting Group.

Assets held by the rich in Brazil, Russia, India and China are set to rise by $2 trillion, or 71 percent, to $4.8 trillion by 2010, the Boston-based research group said today. Millionaires' wealth in the four countries is growing 11 percent a year on average, compared with 5.6 percent elsewhere.

``We are living through great years for the private banking industry,'' Christian de Juniac, who runs the consultant's wealth management unit, said in an interview from his office in London. ``As assets go up, profits go up.''

Growing ranks of millionaires may mean more customers for banks such as UBS AG, the world's largest manager of money for the rich, and Credit Suisse Group. Both banks have said they're planning to expand operations in Asia to win more wealthy clients for their fund management and private banking businesses.

Construction projects in China and India, the fastest growing of the world's 20 largest economies, are spurring demand for commodities such as iron ore from Brazil and oil from Russia.

Millionaires' wealth in the four countries is rising at an even faster pace than economic growth, the report showed. The amount overseen by wealthy people in China and India, the world's two most populous nations, will double by 2010, de Juniac said.

Rising Faster

Overall, there were 7.2 million millionaires in the world at the end of last year, up about 10 percent from a year earlier, with $25 trillion of assets, Boston Consulting said. The U.S. had 3 million, Europe about 2 million, and China about 250,000. The number of millionaires increased 5 percent last year in the U.S. and 20 percent in Asia, the report said.

China already ranks third in the world in sales of luxury goods, according to figures from JPMorgan Chase & Co.

``There is an accumulation effect,'' de Juniac said. ``When a country becomes better off, the rich tend to get a disproportionate amount of that wealth.''

The increase in the number of rich is creating demand for professional wealth management services. ``When people get richer they want their money managed in a professional way,'' de Juniac said. ``They are taking it out of their mattresses.''

Banks Rush In

The boom in wealth is attracting banks including Zurich- based UBS, Britain's Barclays Plc and Citigroup Inc. of the U.S.

UBS Chief Executive Officer Peter Wuffli said in an interview last week that India has ``very big growth potential,'' while China is ``an extremely attractive market for financial companies.'' Last year, UBS paid $500 million for 1.6 percent of Bank of China, the country's No. 2 lender, and in June received the go-ahead from Chinese authorities to set up a joint venture for a brokerage.

Credit Suisse, also based in Zurich, said earlier this month that it plans to at least double the number of employees in Asia over the next two years to tap growing wealth in the region. London-based Barclays plans to start a wealth-management unit in India and hire as many as 50 managers next year to win business in Asia's fourth-largest economy.

Citigroup, the biggest U.S. bank, said in May it will hire as many as 100 people to manage the wealth being created in India, a nation of 1.1 billion people where half the population is less than 25 years old.

The change from agrarian societies into industrial giants is mirrored in the life histories of some Asia's wealthiest. Thirty-seven-year-old Huang Guangyu, China's richest man, started life as a peasant's son. He amassed a $1.7 billion fortune by founding retailer Gome Electrical Appliance Holdings Ltd. in 1987.

Different Approach

The investing approach of clients in Asia differs from those in Europe and the U.S. While Europeans often favor bonds and those in the U.S. prefer stock-related investments, the rich in China and Taiwan are particularly interested in holding their money in cash, de Juniac said.

About 60 percent of wealthy client money in those countries is held in cash accounts, he said. That's because three quarters of millionaires there are entrepreneurs and they prefer to keep control over their assets rather than hand them over to money managers.

They keep the cash in order to do their own trades, he said. That again means a boon for the private banks.

``Not only are they getting more assets, but they are transaction oriented so there are lots of fees,'' he said.