A new report about Americans' preferences for building long-term wealth shows a somewhat surprising aversion to risk.

Flickr User 401(K) 2012

Cash came in first as the preferred way to building wealth, 26 percent preferred a bank account. And those under 30 were most likely to prefer cash, according to Bankrate.com.

"It's troubling that cash is the primary choice for a lot of people when it comes to long-term money," Analyst Greg McBride said.

Twenty-three percent liked real estate long-term, 16 percent favored gold. Only 14 percent liked stocks.

"Money that you're gonna need within the next ten years should not be in the stock market," McBride explained. "But beyond that, you can afford to be more aggressive."

Of course, cash yields are extremely low. The average money-market deposit account yields just 0.11%, according to Bankrate.com, so a $10,000 initial investment would only gain $110.55 over a 10-year period. That hardly seems like enough to meet longer-range financial goals such as retirement.

McBride says many are still gun-shy about stocks, almost five years after the great recession sent shares plunging.