definition 

A tax-free transfer of funds from an IRA into an employer retirement plan such as a 401(k).

commentary 

A reverse rollover can be useful if withdrawals are needed before age 59.5 .  By rolling an IRA to a 401(k), the funds often become penalty-free after age 55 and before age 59.5.  Also, a reverse rollover may make the backdoor Roth IRA Contribution strategy more effective.