NEW YORK — The number of U.S. households with a net worth of more than $5 million, excluding their primary residence, surged 23 percent to surpass one million for the first time in 2006, according to a survey released on Tuesday. The survey by Chicago-based Spectrem Group found that the number of U.S. households with more than $5 million rose from 930,000 in 2005. In 1996, there were only 250,000 U.S. households in the ‘ultra-rich’ category, Spectrem said. ‘The past few years have been nothing but astounding for wealthy Americans,’ said Catherine McBreen, managing director of Spectrem, a consulting group that researches the affluent and retirement markets. McBreen said the surge in household growth is underpinned by economic growth in recent years, which has fueled both stock market gains and also the market for private companies. She also ascribed gains to rising real estate valuations and favorable tax policies. ‘The wealthiest households are the business owners,’ said McBreen. She also said broader ownership of stocks has helped overall household wealth. The survey found that U.S. households that are merely wealthy, defined as having assets of more than $500,000 excluding primary residence, rose 9 percent to […]