1099-R Code 1M: Rollover Window, Penalty, and Reporting

Code 1M on a Form 1099-R means your employer retirement plan wrote off an unpaid loan balance against your account because you left the job or the plan terminated, and you were under 59½ when it happened. The “1” marks the distribution as early; the “M” identifies it as a qualified plan loan offset. Left alone, that offset becomes ordinary income and triggers a 10% early-distribution penalty. Rolled over in time, it costs you nothing.

What the Two Codes Mean Together

Box 7 of a 1099-R can carry up to two distribution codes, and the pair does the reporting work.

Code 1 is “early distribution, no known exception.” The plan administrator uses it whenever a distribution goes out before you reach 59½ and the administrator has no way to confirm that a statutory exception to the 10% penalty applies.¹ It does not mean no exception exists. It means the plan did not apply one, so claiming one is on you.

Code M is “qualified plan loan offset,” which the IRS defines narrowly: a loan offset caused specifically by your separation from service or by termination of the plan.¹ That narrow definition is what unlocks the extended rollover deadline described below. A loan offset that happens for any other reason gets reported without the M and does not qualify.

Why This Happened

Most 401(k), 403(b), and governmental 457(b) plans let participants borrow from their balance and repay through payroll deductions. As long as you stay employed and the payments keep coming, nothing is taxable. Separation changes that. Once you leave, the plan usually demands the remaining balance in full within a short window. If you cannot repay, the plan offsets your account by the unpaid amount and reports that offset as a distribution in Box 1 of a 1099-R, even though no check ever went out to you.¹

Plan termination produces the same result. If the employer shuts down the plan entirely, outstanding loans get resolved, and any balance you cannot pay is offset.

What It Costs If You Do Nothing

The Box 1 amount lands on your return as ordinary income. On a $20,000 offset, a taxpayer in the 22% bracket picks up $4,400 in income tax.

Then the 10% additional tax under 26 U.S.C. § 72(t) applies to the portion included in gross income because Code 1 flagged it as early.² Same $20,000, another $2,000. Over $6,000 in federal tax on money you never received in the year you likely lost your job.

Section 72(t)(2) lists exceptions that can wipe out the 10% penalty, including distributions after separation from service in or after the year you turn 55, certain medical expenses, and qualified domestic relations orders.² The plan will not apply these for you. You claim them on Form 5329 when you file.

The Rollover Window That Fixes It

This is the part worth acting on. A standard plan loan offset gives you the usual 60 days to roll the amount into an IRA or another eligible plan. A qualified plan loan offset, the kind coded M, gets a much longer deadline. Under the rule added by the Tax Cuts and Jobs Act of 2017, you have until the due date of your federal return for the year of the offset, including extensions, to contribute the offset amount to an eligible retirement plan or IRA. For most people that is April 15 of the following year, or October 15 with an extension.

Roll over the full offset amount by that deadline and the distribution is not taxable and the 10% penalty does not apply.

You do not have to use the exact dollars that were offset. The money can come from savings, a new job’s signing bonus, family, anywhere. What matters is that the dollar amount you deposit into the receiving plan or IRA equals the amount in Box 1. Roll over part of it and only that part escapes tax; the rest stays taxable.

Reporting Code 1M on Your Return

The distribution goes on Form 1040. Line 5a shows the gross distribution from Box 1. Line 5b shows the taxable portion.³

If you rolled over the entire offset by the deadline, the full amount goes on Line 5a and zero goes on Line 5b, with an indication that the distribution was rolled over.³

If you did not roll anything over, the full Box 1 amount goes on both 5a and 5b, and the 10% penalty gets addressed on Form 5329.⁴

Partial rollover splits the reporting. Line 5a still carries the full gross distribution. Line 5b carries only the portion you did not roll over. The 10% penalty applies to that unrolled portion unless a § 72(t)(2) exception covers it.

Claiming a § 72(t) Exception on Form 5329

Form 5329 is where you tell the IRS an exception applies even though the plan coded the distribution as Code 1. You enter the distribution amount, look up the exception number in the instructions, and subtract the excepted amount from the penalty calculation. A common case: someone who separated from service at 56 can point to the age-55 separation exception under § 72(t)(2)(A)(v) to eliminate the penalty entirely.² The plan used Code 1 because it did not verify the age at separation. You correct that on Form 5329.

If you rolled the full offset over and owe no penalty, you generally do not need Form 5329, because the distribution is not includible in income to begin with.

If the 1099-R Has the Wrong Code

Errors show up. If a plan reports Code 1 alone without the M, you lose the extended rollover window on paper. Contact the plan administrator or issuer and ask for a corrected form.⁵

If a corrected form has not arrived by the end of February, call the IRS at 800-829-1040. The IRS will contact the payer and ask for the correction. If your filing deadline is closing in, you can file using Form 4852 as a substitute 1099-R, working from your best estimates.⁵ If the corrected form later arrives with different numbers, amend using Form 1040-X.

Reducing the Hit

The single most useful step is rolling over the offset amount before the extended deadline. Cash pulled from any source and deposited into a traditional IRA within the window eliminates the income tax and the 10% penalty on the amount rolled. Because the deposit counts as a rollover rather than a new contribution, it does not use up your annual IRA contribution limit, which is $7,500 for 2026.⁶

Cannot come up with the full amount? Roll over what you can. Every dollar moved into an IRA is a dollar that stays out of income and out of the penalty base.

Running short on time is a solvable problem too. Filing Form 4868 extends your return deadline to October 15, and the qualified plan loan offset rollover deadline moves with it. Those extra six months are often the difference between a full rollover and a five-figure tax bill.

1
Internal Revenue Service. 2025 Instructions for Forms 1099-R and 5498
2
Office of the Law Revision Counsel. 26 USC 72 – Annuities; Certain Proceeds of Endowment and Life Insurance Contracts
3
Internal Revenue Service. Instructions for Form 1040
4
Internal Revenue Service. 2025 Instructions for Form 5329
5
Internal Revenue Service. Topic No. 154, Form W-2 and Form 1099-R (What to Do if Incorrect or Not Received)
6
Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026; IRA Limit Increases to $7,500