The nation's lower- and middle-class workers no longer have a monopoly on the retirement anxiety market: The affluent, it appears, also worry about their ability to retire in comfort, according to a new survey from Wells Fargo & Company.

"We find the rich versus poor narrative in the U.S. is more complex than we might expect, with fears and concerns about retirement now felt along the income spectrum," said Karen Wimbish, director of retail retirement at Wells Fargo. "Even among those considered 'well off,' many seem to fear a sharp drop in their post-retirement standard of living due to insufficient retirement savings.'' 

Several of the survey's findings suggest that affluent Americans are, defined by the study as those with more than $100,000 in investable assets, are less confident about their retirement than they used to be:     

*An estimated 40 percent of affluent Americans say their biggest fear about retirement is they "will do all the right things today and it still won't be enough for tomorrow" while 9 percent fear they "will have under saved and won't recover."

About 23 percent say they are not confident they will have saved enough for retirement. This is especially true for Americans with assets between $100,000 and $250,000 (33 percent); people without a written retirement plan (32 percent) and women (31 percent).

More than one in five between the ages of 60 and 75 say they don't know when they will be able to retire.

Nearly one in five with assets of between $100,000 and $250,000 feel they will need to work until "at least age 80." Among all the affluent surveyed, 12 percent say they will work until 80.

Wells Fargo's survey was produced by Harris Interactive, which conducted a national telephone survey of 801 affluent Americans between the ages of 25 and 75 from Aug. 11 to Sept. 23.

Wells Fargo's survey also indicated that healthcare costs are a significant concern among affluent Americans, with about 28 percent saying that paying health care bills is the leading day-to-day financial concern, followed by 16 percent citing paying monthly bills; and 13 percent indicating saving money for retirement.

The survey also found that affluent women are significantly less confident about retirement than men. The least confident among those surveyed were single women. The most confident were married men.

"Despite the fact that women hold half the high-paying managerial positions in the U.S. workforce and they make a majority of household buying decisions, women continue to lag behind men in their confidence in preparing for retirement and this is particularly true for single women," Wimbish said.