Set it. Forget it. Regret it.

Target-date mutual funds - those investment choices in your college savings plan and retirement account that automatically readjust to cut risk as time passes - went on the fritz big time in 2008.

Congress already plans next week to look into why that happened. Morningstar, the mutual fund rating organization, is ramping up its coverage of the funds.

Losses averaged 23 percent and in some cases exceeded 41 percent, according to research cited in a new Prudential white paper, Strengthening Target-Date Funds with Guarantees to Enhance Retirement Security, released today. The reason seems simple in hindsight. The 2008 market meltdown hit everything in its path like a Gulf Coast hurricane.

But vulnerability to a bear market is only one potential risk that comes with such funds, writes author Christine Marcks. Target-dates also contain what she called a zero balance risk and a purchasing power risk.

Cutting these risks - that you might run out of money too soon or that your retirement income won't keep up with inflation - may require additional action five to 10 years before reaching your target date, Marcks said.

You may have other choices too. But finding them will take more action on your part. Investments don't run well on autopilot.