The new report, Affluent Market Insights 2011, looks at US households with a net worth of $1 million or more, not including primary residence .

It shows that the millionaire population has grown for two consecutive years after the market turmoil of 2008 severely impacted wealth holdings and cut the millionaire population by 27 per cent.

Growth slowed last year from 2009 however, when the millionaire population surged by 16 per cent. 

The number of households with a net worth of $5 million or more also grew by 8 per cent in 2010 and stood at 1.06 million at the end of the year.

"The millionaire comeback continues. After taking a big recession-driven hit in 2008, the US millionaire population staged a second straight year of growth in 2010, adding 600,000 new millionaires,” said George Walper, president of Spectrem Group.

The broader affluent population, with a net worth of at least $500,000 , increased by 6 per cent in 2010, to 13.5 million.

In related news, Spectrem’s latest Millionaire Investor Confidence Index showed that the wealthy are recovering their confidence after the crisis. The index rose 15 points in February to 17, reaching mildly bullish territory for the first time in more than three years.

Affluent Market Insights 2011 is based on surveys of over 3,000 affluent households conducted throughout 2010; an online survey of 1,521 households with a net worth of $100,000 to $1 million fielded in September 2010; an online survey of 997 households with a net worth of $1 million to $5 million carried out in November 2010; and an online survey of 523 households with a net worth of $5 million to $25 million undertaken in November 2010.