Borrowing from a 401(k) can look almost free, since the interest is paid back into the borrower’s own account rather than to a bank. The catch shows up when the job ends. A loan that has not been repaid when a worker leaves an employer does not simply vanish or roll along on its old schedule; it can be converted into a taxable distribution, complete with the early-withdrawal penalty, on money the borrower already thought was spent.
How a loan becomes an offset
While a worker stays employed and keeps making payments, a 401(k) loan is not treated as income. Leaving the job breaks that arrangement. Many plans require the balance to be repaid quickly after separation, and when it is not, the plan reduces, or offsets, the account by the outstanding amount. The IRS explains on its plan-loans page that this offset is treated as an actual distribution from the account. The unpaid balance stops being a loan and becomes money withdrawn, which means it is taxed as ordinary income in the year the offset occurs.
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The penalty stacked on top of the tax
The income tax is only the first layer. Because the offset counts as a distribution, a borrower under age 59½ also owes the 10 percent additional tax that applies to early withdrawals. A worker who borrowed several thousand dollars and left a job before repaying can face a bill that combines ordinary income tax and the penalty on the full unpaid balance, all in a single year, even though no new cash ever reached their hands. The IRS addresses the tax treatment of unpaid loans in its loan FAQs, which describe how a defaulted balance is reported as a taxable event.
The rollover window that can undo the damage
There is a way out, but it runs on a clock. An offset that happens because a worker left the job, known as a qualified plan loan offset, can be rolled over to an IRA or a new employer’s plan. Doing so replaces the offset amount with other funds, so the money stays inside the retirement system and avoids both the tax and the penalty. The deadline is generous compared with the old rules: the rollover can be completed as late as the due date of that year’s tax return, including extensions, as laid out in the IRS guidance on rollovers of retirement-plan distributions. Meeting that deadline requires coming up with the offset amount from another source, which is often the hard part for someone who borrowed out of need.
Why the distinction between default and offset matters
Not every unpaid 401(k) loan is a qualified plan loan offset. A loan that goes into default while a worker is still employed, typically after missed payments, is treated as a deemed distribution, and that version does not qualify for the extended rollover window. The favorable tax-deadline rule applies only when the offset is tied to leaving the job or the plan ending. The difference decides whether a borrower has months to fix the problem or has already lost the chance, which is why the timing and cause of a default are worth confirming with the plan administrator rather than assuming.
The reporting that follows
The event does not stay hidden. The plan issues a Form 1099-R reporting the offset as a distribution, and the amount flows onto the borrower’s tax return whether or not they were expecting it. A worker who ignores the notice can find the balance added to income by the IRS later, with interest. Anyone carrying a 401(k) loan into a job change is better served by mapping the repayment or rollover plan before the last day of work, because once the offset is processed, the options narrow to funding a rollover within the deadline or accepting the tax and penalty. A loan that felt like borrowing from oneself can end as one of the more expensive withdrawals a saver ever makes.
This article was produced with AI assistance and reviewed by The Financial Wire editorial team.
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Warren Cohen is a finance writer based in Phoenix, Arizona, covering personal finance topics including credit, banking, and beginner investing. He earned his degree in business administration from Arizona State University and began his career working in consumer finance, where he gained direct experience with lending and credit systems. He now writes for personal finance websites and fintech platforms, focusing on clear, practical content that helps readers make informed financial decisions.
