Just Put It on My 401(k) Debit Card

And critics argue that in some cases debit cards may encourage unnecessary borrowing. "By making it a debit card, you make it sound like the loan that you take on the 401(k) for everyday purchases," says AARP's Setzfand. "In our opinion, a 401(k) loan should only be taken as a loan of last resort, for a dire medical situation, or if there's no other way to get a home loan, not to go shopping."

Indeed, a November study by the U.S. Government Accountability Office into the country's low retirement savings rate found that preretirement access to funds may lead to lower retirement savings, though it also cited evidence that a loan feature increases retirement plan participation.

Using ReservePlus loans as a mechanism to increase retirement savings participation just makes sense for some demographics, says Young. The participation rate for the GenY age group is low because people "don't want to tie their money up in a program they can never access during their working years. People want to be in control of their retirement plan savings, and when they feel in control, they're more likely to participate or contribute at higher levels." And it makes stable lending possible for seasonal employees and industries with high employee turnover.

Fred Barstein, president and chief executive of 401(K) Exchange, adopted ReservePlus for his employees almost a year ago. He says the program hasn't changed the frequency with which his workers take out loans against their retirement, or the size of their loans, but it has created a stable loan program for his largely transitory work force -- about 75 of his 110 employees work in the call center. As the head of a company, who helps plan sponsors and advisers find the right plan, he says, it was particularly important for him to provide his employees with a "state of the art plan."