If your 401(k) loan defaults, the unpaid balance is treated as a distribution and taxed as ordinary income at your federal rate of 10% to 37%, and if you are under 59½ the IRS adds a 10% early distribution penalty on top. That is the 401(k) loan tax penalty in plain terms. On a $20,000 defaulted balance for someone in the 24% bracket and under 59½, the federal cost alone runs about $6,800 before state tax.
What Actually Triggers the Tax
Two different events can turn a loan into a taxable distribution, and the difference matters because only one of them can be undone.
A Deemed Distribution From Missed Payments
When you miss a scheduled loan payment, the plan can treat your outstanding balance as a deemed distribution. Most plans give you a grace period to catch up, but that window cannot extend past the end of the calendar quarter after the quarter your payment was due. A February payment, for example, has a cure period that runs no later than June 30. Make up the missed payment plus accrued interest before that deadline and the loan stays intact.1Internal Revenue Service. Issue Snapshot – Plan Loan Cure Period
Miss the cure deadline and the entire remaining balance becomes a deemed distribution as of the original missed-payment date. Here is the part that catches people off guard: a deemed distribution does not actually remove money from your account. You owe income tax on the balance as though you had withdrawn it, but the loan often stays on the plan’s books. You still owe the plan, and you have paid tax on money you never held.
A Loan Offset After Leaving the Job
A loan offset happens when the plan uses your remaining account balance to cancel the outstanding loan, usually because you left the employer, the plan terminated, or another distributable event occurred. Unlike a deemed distribution, an offset actually reduces your account, and the offset amount is treated as a taxable distribution.2Internal Revenue Service. Plan Loan Offsets
What the Default Actually Costs
The defaulted balance lands on your tax return as ordinary income for the year of the default or offset. For 2026, federal rates run from 10% to 37%.3Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 If you live in a state with an income tax, the same amount is taxable there, at rates from 2.5% to over 13%; eight states have no income tax at all.
If you are under 59½ at the time of the default or offset, Section 72(t) adds a 10% early distribution penalty on the taxable amount.4Office of the Law Revision Counsel. 26 USC 72 – Annuities; Certain Proceeds of Endowment and Life Insurance Contracts
Concrete numbers help. Say you default on a $25,000 balance at age 40, and the added income leaves you in the 24% federal bracket with a 5% state rate:
- Federal income tax: $25,000 × 24% = $6,000
- Early distribution penalty: $25,000 × 10% = $2,500
- State income tax: $25,000 × 5% = $1,250
- Total: $9,750
That is nearly 39% of the balance, all in one tax year. If the added income pushes you into a higher bracket, the effective rate climbs.
The Withholding Problem
With a deemed distribution, no cash actually leaves your account, so the plan typically withholds nothing for taxes. You owe the full bill when you file. A loan offset can leave you short on withholding too, because the plan applies your balance to the debt rather than distributing cash you could set aside. Making an estimated tax payment as soon as you learn of the default can head off an underpayment penalty on top of everything else.
Rolling Over a Loan Offset to Erase the Tax
A loan offset produces a taxable distribution, but you can undo it by rolling the offset amount into an IRA or another eligible retirement plan. Contribute an amount equal to the offset into an IRA within the rollover window and the distribution is excluded from income and the 10% penalty does not apply.2Internal Revenue Service. Plan Loan Offsets
The window depends on the reason for the offset. For an ordinary loan offset, you have 60 days from the date of the distribution. But a qualified plan loan offset, or QPLO, gets a much longer deadline. A QPLO is an offset that happens because the plan terminated or you separated from service, where the loan was in good standing before that event. For a QPLO, you have until your tax filing deadline for that year, including extensions. A six-month extension pushes the deadline from mid-April to mid-October.2Internal Revenue Service. Plan Loan Offsets
The catch is finding the cash from another source, since the plan already spent your account balance paying off the loan. You are funding the IRA rollover out of pocket. For a $25,000 offset that would otherwise cost $9,750 in taxes, that is usually still the right trade.
Note the boundary: this rollover option does not apply to deemed distributions. A deemed distribution is not an eligible rollover distribution because no money actually left the plan.
Exceptions to the 10% Early Distribution Penalty
The ordinary income tax on a defaulted balance is unavoidable. The 10% penalty is not, if your circumstances fit one of the statutory exceptions.5Internal Revenue Service. Exceptions to Tax on Early Distributions
- Separation from service during or after the calendar year you turn 55, for distributions from that employer’s plan. Public safety employees of state or local governments qualify at 50.
- Disability, defined as being unable to perform any substantial work because of a condition expected to result in death or last indefinitely.
- Unreimbursed medical expenses that exceed 7.5% of your adjusted gross income, to the extent of that excess.
- Distributions paid to a former spouse or dependent under a qualified domestic relations order.
- An IRS levy on the account to satisfy a tax debt.
SECURE 2.0 added more exceptions. These apply more naturally to loan offsets (where cash actually moves) than to deemed distributions. A terminally ill individual, certified by a physician as expected to die within 84 months, can take penalty-free distributions with no dollar cap and repay them to an IRA within three years.6Internal Revenue Service. Notice 2024-02 – Miscellaneous Changes Under the SECURE 2.0 Act of 2022 A domestic abuse victim can take up to $10,500 in 2026 or 50% of the vested balance, whichever is less, based on self-certification that the abuse occurred within the prior 12 months.7Internal Revenue Service. Notice 2025-67 – 2026 Amounts Relating to Retirement Plans and IRAs Emergency personal expense distributions of up to $1,000 per year are penalty-free, and qualified birth or adoption distributions up to $5,000 per child are exempt and can be repaid within three years.5Internal Revenue Service. Exceptions to Tax on Early Distributions
Avoiding a Second Tax Later on the Same Money
A deemed distribution taxes you on money that stays inside the plan, so there is a real risk of being taxed twice: once when the loan defaults, and again when you withdraw the funds years later. The IRS handles this through basis.
If you keep making payments on the defaulted loan after the deemed distribution, each payment adds to your cost basis in the plan. When you eventually take real withdrawals in retirement, the portion attributable to that basis comes out tax-free.8Internal Revenue Service. Retirement Plans FAQs Regarding Loans Even if you stop paying, the amount already taxed should be tracked as basis. Keep your own records. Plan administrators do not always carry this forward accurately across employers or rollovers, so save every 1099-R and loan statement.
Suspending Payments to Prevent the Default
If you are about to miss a payment because of a leave or military service, a formal suspension can stop the default before it starts.
Non-Military Leave
During a bona fide unpaid leave of absence, or when your pay drops below the loan installment amount, the plan can suspend the level-amortization requirement for up to one year. Interest continues to accrue. When you return or the year runs out, whichever comes first, payments resume at amounts high enough to clear the loan (including accrued interest) by the original five-year deadline. The plan cannot extend the term.9eCFR. 26 CFR 1.72(p)-1 – Loans Treated as Distributions
Military Service Under USERRA
Active-duty service gets more generous treatment. A plan suspension during uniformed service does not count against the five-year clock, however long the service lasts, and the loan term is extended by the length of service. The suspension alone will not cause a deemed distribution.10Office of the Law Revision Counsel. 26 USC 414 – Definitions and Special Rules When you return, payments resume at roughly the same installment size over the remaining extended term.9eCFR. 26 CFR 1.72(p)-1 – Loans Treated as Distributions
Not every plan applies these suspensions automatically. Confirm with your plan administrator before you stop paying. If the plan does not formally suspend the loan, a missed payment starts the default clock no matter the reason behind it.
How It Shows Up at Tax Time
The plan reports a deemed distribution or loan offset to you and the IRS on Form 1099-R. The taxable amount appears in Box 1 (gross distribution) and Box 2a (taxable amount).11Internal Revenue Service. Instructions for Forms 1099-R and 5498
Box 7 carries the distribution code. A deemed distribution from a missed payment is usually coded L (loan treated as a distribution) or 1 (early distribution, no known exception). A loan offset after separation may show 1 or 2 (early distribution, exception applies). The code tells the IRS whether to expect the 10% penalty.11Internal Revenue Service. Instructions for Forms 1099-R and 5498
If Box 7 shows Code 1 but you actually qualify for a penalty exception, file Form 5329 with your return to claim the exception and compute the correct penalty, which may be zero. If Code 1 is correct and no exception applies, you can report the 10% additional tax directly on Schedule 2 of Form 1040 without filing Form 5329 separately.12Internal Revenue Service. Instructions for Form 5329
Because deemed distributions usually generate no withholding, adjust your W-4 or make an estimated payment for the quarter in which the default occurred. Waiting until you file to deal with a five-figure tax bill invites an underpayment penalty on top of the taxes you already owe.