NEW YORK (CNNMoney.com) -- Wealth is becoming ever more concentrated among the richest of the rich worldwide.
Thanks to strong growth in market capitalization and GDP, the ranks of the wealthy - and ultra wealthy - have risen, along with their total assets, according to findings from a report released Wednesday.
In 2006, the number of people with more than $1 million in investable assets - not including the value of their homes - rose 8.3 percent to 9.5 million worldwide, according to Merrill Lynch and Cap Gemini, in their annual World Wealth Report.
Their assets were worth $37.2 trillion in 2006, up 11.4 percent from a year earlier. That marked the first time in seven years that their annual asset growth exceeded 10 percent.
Those who enjoyed the greatest growth, however, both in terms of their numbers and their assets, were what Merrill Lynch and Cap Gemini call ultra-high-net-worth individuals, defined as those with investable assets of at least $30 million. Members of that club rose 11.3 percent to 94,970, and their asset pool increased by 16.8 percent to $13.1 trillion.
Singapore, India, Indonesia, Russia, United Arab Emirates, and China were among the top 10 countries with the largest growth in their wealthy population. In that group, Russia boasts the greatest number of high net worth peope at 119,000.
Growth was slowest in North America and Europe, even though the wealthy in those regions account for more than half of the world's wealthiest in terms of numbers and assets.
In North America, the number of millionaires grew 9.2 percent to 3.2 million, of which 2.9 million were in the United States, and their assets rose 10.3 percent to $11.3 trillion. The only other region with slower growth was Europe, whose millionaire ranks increased by 6.4 percent to 2.9 million, and their assets rose 7.8 percent to $10.1 trillion.
The report also found that high net worth individuals gave $285 billion to philanthropic causes, or less than 1 percent of their total assets. The amount of assets in socially responsible investments was $2.29 trillion - or about $1 of every $10 invested in U.S. public equities.
Merrill Lynch and Cap Gemini analysts predict that financial wealth among the high net worth population globally will increase by an annual rate of 6.8 percent in the next few years, hitting $51.6 trillion by 2011. 
