Investors' risk aversion even applies over long investment horizons, with Americans most commonly saying that cash investments are the best way to invest money not needed for more than 10 years, according to a new Bankrate.com report.

More than one in four Americans (26%) favor cash, edging out real estate (23%). One in six (16%) favor gold or other precious metals, even though those investments have been pummeled in 2013, while only 14% say stocks would be their choice. Just eight percent of Americans chose bonds.

"Americans not saving enough is well-documented, but hunkering down in cash investments and settling for low returns will only magnify the problem of not having a sufficient nest egg to meet longer-range financial goals such as retirement," said Greg McBride, CFA, Bankrate.com's senior financial analyst. "Other choices may not do the trick either, as real estate is not only very cash-intensive, but often illiquid. And precious metals spit out zero cash flows, with gains solely dependent on price appreciation."

According to Bankrate.com, the average money-market deposit account yields just 0.11%, so a $10,000 initial investment would only gain $110.55 over a 10-year period. And the average five-year CD currently yields just 0.78%.

The Bankrate.com Financial Security Index is down slightly in July from last month's record, from 102.7 to 102.0. However, this is still the second-highest level on record (dating back to Dec. 2010).

Americans continue to exhibit positive feelings concerning four of the five components of financial security – job security, debt, net worth and overall financial situation – with savings as the laggard.

Net worth continues to improve, mainly due to the housing market, but also somewhat thanks to the stock market. Those reporting higher net worth compared to one year ago (29%) outnumber those reporting lower net worth (16%) by nearly two to one.

The survey was conducted by Princeton Survey Research Associates International (PSRAI) and can be seen in its entirety here: http://www.bankrate.com/finance/consumer-index/financial-security-charts-0713.aspx