The Universal Millionaire Rumble

Household wealth is hitting record heights, and not just in the U.S. There are more millionaire households on the planet than ever before, particularly in Europe and in China, where growth rates are highest.

The total number of world millionaire households—those with assets of $1 million or more—grew by 14% in 2006, to 9.6 million, representing the richest 0.7% of all households and owning $33.2 trillion, or about a third of the world's wealth, according to a recent study by the Boston Consulting Group, a global management consulting firm."

It's sort of a sexy thing, looking at managing relationships on a household level," says Bruce Holley, a New York-based partner with BCG, of the study. This is the first global wealth report from BCG that estimates the number of millionaire households per country, as well as estimating total wealth. "This year's report, our seventh, examines the greatest source of organic growth within wealth management players: namely, their human assets," write Holley and his colleagues in the report's preface.

China's Rising—Fast---------------------------------The U.S. had, by far, the highest number of millionaire households, with nearly 4.6 million, and the highest number of $100 million-plus households, with 2,300. The number of millionaire households increased by a steady 10%, while $100-million-plus households grew by 7%, joining the ranks of Microsoft Chairman Bill Gates and Berkshire Hathaway Chief Executive Warren Buffett.

Japan, Britain, Germany, and China round out the rest of the top five countries with the most millionaire households, in that order. The number of millionaire households increased the most last year in China (up 39%), Spain (up 32%), and Britain (up 30.5%).

In Europe, the number of millionaire households grew by 26.4% in 2006, the highest of any region in the study, helped by its strong currency against the weakening U.S. dollar. In North America, millionaire households grew by just 9% in 2006.

The United Arab Emirates and Switzerland led the ranking for highest density of millionaire households, with millionaire households accounting for 6.1% of all households in each country—almost nine times the global average.

Japan, Britain, Germany, and Italy have the most households in the $100 million-plus bracket, and in terms of growth, China (up 74%), Brazil (up 27%), and Russia (up 26%) saw the highest rates last year.

"China is a force to be reckoned with," says Holley, noting that the country's total assets under management have grown at an annualized rate of 23% over the past five years. China's newest billionaire residents will find themselves in the company of powerful businessmen like Suntech Power's Shi Zhengrong, who lives in the city of Wuxi.