The number of US households with a net worth of USD1 million or more, not including primary residence (NIPR), reached a record 10.4 million in 2015, according to Spectrem Group's Market Insights Report 2016. 

The total is an increase of approximately 300,000 households, up from 10.1 million in 2014.
Spectrem Group's annual report analyses the number of households in America based on net worth, from the Mass Affluent to the USD25 million-plus segment. The report also includes information on how the affluent investors invest, where they invest, and what they expect from their investments.
In 2015, there were 29.8 million Mass Affluent households with a net worth between USD100,000 and USD1 million, NIPR.
The number of Millionaires, with a net worth between USD1 million and USD5 million, reached 9.1 million.
The Ultra High Net Worth market, those households whose net worth is between USD5 million and USD25 million, NIPR, grew to 1,210,000, an increase of 42,000.
The number of USD25 million-plus households grew by 3,000 to 145,000.
"Despite ongoing concerns about market volatility and the direction of the US economy, the number of affluent American households expanded in 2015," says George Walper, Jr, President of Spectrem Group. "This report underscores that wealth creation continues to occur in the United States, with the number of millionaire households growing by more than 3 per cent in 2015."
While all affluent US households have experienced significant wealth expansion since 2008 – the depth of the Great Recession – the greatest increase has occurred among the wealthiest households. The number of households reporting USD25 million-plus in net worth grew by nearly 73 percent, compared with growth of 59 percent for Ultra High Net Worth households, 54 per cent for Millionaire households, and 22 per cent for Mass Affluent households, respectively.