American millionaires are becoming a rarer breed.

Though there are more millionaire households in the U.S. than anywhere else in the world — 5.1 million — that number fell by 129,000 in 2011, according to a study put out last week by the Boston Consulting Group.

Worldwide, millionaires were on the rise, the study found — particularly in China and India, thanks to growth fueled by IPOs and entrepreneurs.

The number of households worth over $1 million in cash, stock and other assets (excluding property, businesses and luxury goods) went up by a total of 175,000.

Japan and China ranked 2nd and 3rd behind the U.S. in terms of total number of millionaires, with 1.6 million and 1.4 million respectively, but Singapore took the title for country with the highest density of millionaires.

More than 17% of all households in Singapore qualify for millionaire status — roughly one in six — while 10 out of every 10,000 homes fall into “ultra-high-net-worth” territory, defined as having the equivalent of $100 million in private wealth.

Switzerland beat out Singapore for the most ultra-wealthy, however, with 11 out of every 10,000 homes categorized in that range.

While the U.S. shed millionaires in 2011, it seemed to be a good year for the ultra-wealthy — that segment of the population saw their wealth grow by 3.6%, while the average growth across other households was 1.7%.

The study, titled “The Battle to Regain Strength,” is the consulting firm’s 12th annual report of its kind, and predicts wealth will continue to become more concentrated among the ultra-rich in the coming years.

While the ultra-high-net-worth households currently hold 5.8% of global private weath, or $7.1 trillion dollars, that number is expected to jump to 6.8% or $10.3 trillion by the end of 2016.

(Source: NY Daily News)