More than one-third of baby boomers expect Social Security to be a major source of income in their retirement, yet only one in four have confidence the system will have the money to pay these benefits throughout their retirement, according to the MFS Investing Sentiment Survey.

Nearly 40 percent of those surveyed for this study were not at all confident Social Security would still be around for them to tap into in retirement.

Most investors recognize that personal savings and investments are the most important factors in funding their retirements, but baby boomers, who at the median are only eight years away from retirement, have very little saved for retirement. Only 12 percent of respondents had $1 million or more saved in retirement accounts and the median balance was $314,000.