America's millionaires are feeling the pinch. The number of U.S. households with a net worth of $1 million or more, not including primary residence (NIPR), grew just 2% in 2007 to 9.2 million, up from 9 million the year before, according to a new report, "Affluent Market Insights 2008," released today by Spectrem Group.

While the 9.2 million households does represent a record for millionaires, it comes on the slowest growth rate since 2003, when growth was zero. It also compares with advances of 8% in 2006, 11% in 2005 and 21% in 2004.

At the same time, Ultra High Net Worth households, those with a net worth of $5 million or more (NIPR), advanced 2% in 2007 to a record 1.16 million - on the slowest growth since zero in 2002. This represents a significant slowdown from advances of 23% in 2006 and 26% in 2005.

"The substantial gains in the number of millionaire and Ultra High Net Worth households we've seen since the end of the dot-com bust has all but ground to halt. Even as both groups' ranks reached new highs in 2007, growth was practically flat. We had already tracked a steady decline in millionaires' investment optimism since mid-2007 on a variety of concerns including a slowing economy, rising energy costs and poor stock market conditions. It now appears those concerns have become a reality for the wealthiest tiers of the U.S. population," said George H. Walper