Moving your 401(k) plan money to a new employer's retirement plan or to an IRA is called a rollover.
"These are generally the two good choices," said Cohen at CF Services Group. "It works if you're moving to a company with a robust 401(k) plan or to an IRA and can invest in [almost] anything, including low-cost index funds."
If your new employer's 401(k) plan accepts rollover contributions from an old plan, it can make sense to do it because you are consolidating your retirement assets and can better manage your investments.
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You also can move your 401(k) plan money to a rollover IRA. If done properly, it's a tax-free event.
But again, be aware of the different rules applying to 401(k) plans and IRAs.
One advantage to moving 401(k) money to an IRA deals with distributions if you are in retirement, Sullivan said. All 401(k) distributions include a 20 percent withholding for taxes whether or not you actually owe that much at tax time. With an IRA, she said, you can control the amount of tax withholding.