The ultra-high-net-worth investor has developed a growing appetite for hedge funds and other alternative investments, a new report by Spectrem Group says. A survey of more than 100 households with net worth of $25 million or more, excluding primary residence, found that half had hedge fund exposure in their portfolios, up from 35 percent three years earlier. The average balance in hedge funds, however, was down nearly 20 percent in that period, reflecting the hammering that the funds experienced after the financial crash. Many respondents are investment professionals, Spectrem says, so it's not unusual that hedge funds would find a place in their portfolios.