Higher-return investments are needed to keep abandoned 401(k)s from being eaten up by fees before their participants or their heirs remember them, General Accountability Office, the investigative arm of Congress, said in a report Monday.

Another recommendation GAO made is for Congress to create a national pension registry to lessen the chance that workers would abandon some of their pensions.

Under existing law, if a worker leaves a job and has left behind a 401(k) with less than $5,000 and no directions on what to do with the money, the employer can “force-transfer” the sum into an individual retirement account (IRA).

Abandoned retirement accounts of $20,000 if less can also be transferred to IRAs if more than $5,000 isn’t from rollovers.

Currently, Department of Labor regulations require money from forced transfers to be put into low-risk, low-yield, short-term investments such as money market mutual funds and certificates of deposit that GAO said lack the potential for low term growth retirees should have.

With the high turnover rate in the American work force, the amount of money in these abandoned 401(s) that is transferred to low-producing IRAs is in the billions, according to the study.

The agency added management fees can outpace the low yields forced transferred pensions are getting now.

“In recent years, the typical forced-transfer IRA investment, such as a money market account, has earned almost no return,” GAO said.