A strong global economy gave 600,000 people an entree last year into a highly envied group: the world's millionaires.

The annual World Wealth Report (search), released Thursday by Merrill Lynch & Co. Inc. (MER) and the Capgemini Group (search) consulting firm, found that there were 8.3 million people worldwide with $1 million or more in financial assets at the end of 2004, up from 7.7 million a year earlier.

Their total wealth rose 8.2 percent to $30.8 trillion in 2004, giving them control of nearly a quarter of the world's financial assets, according to Petrina Dolby, vice president of Capgemini's wealth management practice.

The 8.2 percent increase was the strongest since an identical 8.2 percent rise in 1999, she said.

Not surprisingly, the expansion of the millionaire class was especially strong in North America because of the solid economic growth last year in both the United States and Canada.

"Significantly, North America surpassed Europe both in total high net worth individuals population and wealth for the first time since 2001," when North American investors were hard-hit by the bursting of the technology stock bubble and the terror attacks on the World Trade Center and Pentagon. The Asia-Pacific region also showed strong growth.

According to the latest figures, the number of high net worth individuals included 2.7 million in North America with a total of $9.3 trillion in assets; 2.6 million in Europe with $8.9 trillion; 2.3 million in the Asia-Pacific region with $7.2 trillion; 300,000 in Latin America, including Mexico, with $3.7 trillion; 300,000 in the Middle East with $1 trillion; and 100,000 in Africa with $700 billion.

The study also looked at what it termed "ultra high net worth individuals," who have at least $30 million in financial assets.

Their ranks increased by 6,300 individuals, or 8.9 percent, in 2004 to 77,500 worldwide, the study said.

Although the international economy was growing rapidly last year, the world's millionaires were more cautious in their investment and asset allocation strategies, the study said.

"With returns drifting lower and market volatility increasing in 2004, high net worth individuals leveled off their commitments to equities," it said.

The wealthy decreased their stock holdings to 34 percent last year from 35 percent in 2003 and increased their fixed-income investments to 27 percent last year from 25 percent the year before. Their other holdings in 2004 were 12 percent in cash and other liquid investments, 13 percent in real estate and 14 percent in "alternative" investments such as hedge funds and commodities.

The real estate portion of their holdings was down from 17 percent in 2003, the report said.

"We believe this relatively low allocation rate signals high net worth individuals' desires to harvest returns from now premium-priced (real estate) holdings to direct profits into other asset classes," the report said.

Although the global economic expansion has begun slowing, the study still predicts 6.5 percent growth over the next five years — enough to create many more millionaires, especially in North America.

It forecasts that by 2009, the high net worth individuals will have amassed $42.2 trillion in assets. By region, it will include $13.9 trillion in North America, $10.7 trillion in Europe, $10.1 trillion in the Asia-Pacific region, $5 trillion in Latin America, $1.5 trillion in the Middle East and $900 billion in Africa.