Money management firms frequently offer workers misleading and self-serving information about how to handle their retirement savings when they change jobs, according to a Government Accountability Office report to be released Wednesday.

Departing workers are often encouraged to roll their accounts into individual retirement accounts, or IRAs, run by the firms that already manage their retirement money, even when it would be best for employees to keep the money in a 401(k), the GAO investigation concluded. Having workers move their money into IRAs typically allows money management companies to harvest bigger fees for handling the retirement money, the report said.

“The financial services industry spends substantial time and effort into marketing IRAs that may not be in the best interests of account holders,” said Rep. George Miller (D-Calif.). “This comes as no surprise, since IRAs often come with higher costs when compared to a 401(k).”

The GAO had undercover investigators call 30 money management firms posing as workers about to change jobs in an effort to learn how money managers market their services. In seven cases, they were given incorrect information, including that moving their money into an IRA would be “free,” even though workers would incur ongoing fees by opening the accounts. The GAO also reviewed the Web sites of 10 large firms and found that five incorrectly said their IRAs were free.

“Saving for retirement is tough enough, so it’s terrible when employees lose hard-earned money to misleading sales pitches, harmful products or just poor investment advice,” said Sen. Bill Nelson (D-Fla.), chairman of the Senate Special Committee on Aging.

The GAO report comes amid concern among policymakers about the increasing number of Americans who are unprepared for retirement. Profound changes in the nation’s employee benefit structure and growing calls to trim Social Security and Medicare spending, the mainstays of retirement security, have left workers with a greater burden to prepare for their retirements.

But many are not meeting the challenge. About half of employees have no retirement plan at work. And among the private-sector workers who do, only one in five is covered by a pension that guarantees a set amount of income throughout retirement. The others are covered by defined contribution plans such as 401(k)s. But, experts say, workers often do not save enough or they too frequently tap the money for non-retirement purposes.

Industry analysts point out that 401(k)s can provide adequate retirement security, provided people save money in them consistently, while minimizing the amount lost to fees.

Besides allowing workers to save for retirement, the $3.5 trillion they have in 401(k)s provides a lucrative stream of revenue for fund managers. Money that employees move out of 401(k)s when they change jobs accounts for 90 percent of all new funds flowing into IRAs, the GAO report said.

When workers leave a company, they generally have four choices for handling their 401(k)s: leave the money in their former employer’s plan, move it to their new employer’s plan, put it in an IRA, or withdraw it and use it for current expenses. The latter option makes them liable for a tax penalty if the employee is younger than 591 / 2.

The GAO said the options are often confusing, making workers vulnerable to any misinformation they receive from the companies handling their accounts.

“When Americans call up their 401(k) plan provider looking for advice, they shouldn’t be inundated with marketing materials masquerading as objective, investor education, but that is exactly what is happening to many individuals,” said Sen. Tom Harkin (D-Iowa), chairman of the Senate Health, Education, Labor and Pensions Committee. “Some unscrupulous firms are making a profit by keeping customers in the dark.”

Miller, Nelson and Harkin have written a letter to the Labor and Treasury departments calling for uniform disclosure notices to make it easier for account holders to make better-educated decisions. They called for IRA fees to be more clearly stated and for new rules encouraging workers to keep their retirement savings in the 401(k) system rather than IRAs.

Rachel McTague, director of media relations for the Investment Company Institute, which represents the mutual fund industry, said plan sponsors typically are forthcoming with account holders.

The plans “provide full information about participants’ options when workers separate from the plan — including the option, when available, of maintaining their assets in the plan,” she said.