BOSTON (TheStreet) -- Fear of unexpected expenses is largely to blame for leading even more-affluent Americans to rely heavily on low-yield savings accounts, CDs and money market funds as they save for retirement, despite their admitted dissatisfaction with returns.That was the conclusion drawn from research released this month by MetLife ( MET - Get Report). Its poll, conducted online in September by Harris Interactive, surveyed 1,858 Americans age 45 and older, including 500 people with between $200,000 and $1 million in investable assets. Accepting lower returns was seen as a trade-off to ensure fast access to funds. Among those with more than $200,000 in investable assets, half reported having at least one unexpected expense in the past year that cost $2,000, and 29% had between two and five major unexpected expenses. Forty-five percent said they were forced to dip into assets and 32% used liquid investments such as CDs. More than one in five used a credit card or other revolving debt; 9% took out a home equity loan; and 4% borrowed from a retirement savings plan. Many say they have to account for not only their own emergency needs, but those of younger and older family members -- and friends as well. Compared with the general population, affluent investors are much more likely to have changed the way they invest for retirement as a result of the financial crisis, MetLife's analysis showed. More than half said they changed the way they invest, versus 29% of the general population. While 65% of more-affluent Americans are using mutual funds as a vehicle to save for retirement, a large segment, 52%, are using bank savings accounts. Fifty-one percent say they are using money market accounts and 38% are using CDs. Other, less popular, savings vehicles used include Treasury/savings bonds, municipal bonds and fixed annuities. Hand-in-hand with a desire for liquidity is an aversion to risk. When asked what is required when planning for retirement today, "understanding their tolerance for risk" was the top response (71%), beating out "understanding the various investment options." Only 53% said the "help of a professional financial adviser." The events of the recession led many to "radically change their perspective of risk," says Julia Lennox, vice president of retirement products at MetLife. "They are more realistic about what their risk profile really is." As Lennox sees it, many of the concerns facing the affluent can be summed up in one word: control. The lesson for financial advisers is to help clients understand that greater returns can be achieved without sacrificing this desire or jeopardizing a secure retirement. "There are many ways of creating liquidity without derailing your plan," she says. One such example is the need to better explain the full range of annuity products. When looking for a tax-advantaged saving vehicle, the more-affluent would consider tax-exempt municipal bonds (63%); fixed annuities (28%) and variable annuities (23%) lagged behind. Lenox said a challenge for annuity providers such as MetLife is to do a better job educating investors of the many options offered in the annuity marketplace and cutting through the perceived complexity that continues to deter many. Despite talk of the "new frugality," many of the more-affluent investors saw little wiggle room in reducing their expenses. Nearly half say that if they cut discretionary spending by 10% or less it would "mean a dramatic change in lifestyle." "What you are seeing is that people's lifestyles are eating up the resources they have, and there are limited ways of dealing with that," Lennox says. -- Written by Joe Mont in Boston. >To contact the writer of this article, click here: Joe Mont. >To follow the writer on Twitter, go to http://twitter.com/josephmont. >To submit a news tip, send an email to: firstname.lastname@example.org.