These clients may come back into the equity markets in a big way this year, says a new survey.

According to Ultra High Net Worth Investor 2010, a new report released today by Spectrem Group, more than half (52%) of U.S. households with a net worth between $5 million and $25 million, not including their primary residence, say they are likely to purchase equities over the next 12 months.

This makes equities, which include individual stocks and stock mutual funds, the most popular investment choice for ultra high-net-worth investors in 2011, surpassing other options such as cash (35%), international investments (33%) and fixed income products (31%).

Ultra-high-net-worth households had average cash balances, including money market funds, checking, savings, Treasury Bills and CDs, of $659,000 at the end of 2010. This represented 10% of their total investable assets.

The Spectrem report is based on a survey of 516 households with a net worth of $5 million to $25 million, not including their primary homes, conducted in November 2010. Its data has a margin of error of plus or minus 4.3 percentage points.