Yes, the IRS will almost certainly catch a missing 1099-R. Every payer that issues one sends a copy directly to the IRS, and the agency’s automated system compares those records against what you filed. When a distribution shows up in their records but not on your return, you get a notice. Fixing the omission yourself before that happens is cheaper and gives you control over how the correction goes.
How the IRS Matches 1099-R Income to Your Return
Financial institutions, insurance companies, and plan administrators file Form 1099-R with the IRS electronically for every retirement distribution they pay out.1Internal Revenue Service. 2025 Instructions for Forms 1099-R and 5498 Those records flow into the Information Returns Master File, which ties reported income to your Social Security number. The Automated Underreporter program then compares payer data against the figures on your Form 1040.2Internal Revenue Service. 4.19.3 IMF Automated Underreporter Program
When the system spots a distribution missing from your return, a tax examiner reviews the file and issues a CP2000 notice. It’s not an audit and not a bill. It’s a proposal stating the IRS believes you owe more tax because of income you didn’t report, with a proposed adjustment, penalties, and typically 30 days to respond.3Internal Revenue Service. Topic No. 652, Notice of Underreported Income – CP2000
The matching doesn’t happen right after you file. It can take a year or more for the comparison to catch up to your return. That lag fools people into thinking the omission was missed. It wasn’t. The queue just hadn’t reached it yet.
Check the 1099-R Before Assuming You Owe Tax
Not every 1099-R means additional tax. Two boxes on the form decide what you’re actually looking at: Box 2a (taxable amount) and Box 7 (distribution code).
The most common false alarm is a direct rollover. If you moved money from a 401(k) to an IRA, the payer still issues a 1099-R, but Box 2a should show zero and Box 7 should show Code G.1Internal Revenue Service. 2025 Instructions for Forms 1099-R and 5498 You still have to report the distribution — you enter the gross amount and then zero as the taxable portion — but no tax is owed. Leaving the form off entirely triggers an inquiry anyway, because the IRS’s system only sees an unreported distribution.
Look at Box 4 too. That’s federal income tax already withheld from the payment.4Internal Revenue Service. Form 1099-R Distributions From Pensions, Annuities, Retirement or Profit-Sharing Plans, IRAs, Insurance Contracts, etc. You get credit for that on your return. In some cases withholding covers the full tax on the distribution, and occasionally more. People who amend for a forgotten 1099-R often find they owe less than they feared once withholding gets counted.
What It Costs If You Do Nothing
The bill for an unreported 1099-R stacks in layers, and the layers keep growing until you pay.
Interest
Interest on unpaid tax runs from the original filing deadline, not from the date the IRS catches the error. The rate is the federal short-term rate plus three percentage points, adjusted quarterly.5Office of the Law Revision Counsel. 26 U.S.C. 6621 – Determination of Rate of Interest For the first quarter of 2026, that rate is 7% for individual underpayments.6Internal Revenue Service. Quarterly Interest Rates Interest compounds daily and applies to both the tax and any penalties.
Failure-to-Pay Penalty
The IRS adds 0.5% of the unpaid tax for each month or partial month the balance sits unpaid, capped at 25%.7Office of the Law Revision Counsel. 26 U.S.C. 6651 – Failure to File Tax Return or to Pay Tax On a $5,000 underpayment, that’s $25 a month before interest.
Accuracy-Related Penalty
A large omission can also draw a 20% accuracy-related penalty on the underpayment tied to negligence or a substantial understatement of income tax.8Office of the Law Revision Counsel. 26 U.S.C. 6662 – Imposition of Accuracy-Related Penalty on Underpayments A forgotten $3,000 pension check probably won’t hit that threshold. A $50,000 IRA withdrawal left off a return is more likely to look like negligence than oversight.
The 10% Early Withdrawal Penalty
If the distribution came from a retirement account before you turned 59½, you likely owe an additional 10% tax on top of ordinary income tax.9Office of the Law Revision Counsel. 26 U.S.C. 72 – Annuities; Certain Proceeds of Endowment and Life Insurance Contracts It applies to the taxable portion and gets reported on Schedule 2. Box 7 tells you what the payer flagged: Code 1 is an early withdrawal with no known exception, Code 2 means an exception applies, Code 3 is disability, and Code 4 is a death benefit. Codes 3 and 4 don’t trigger the penalty.10Internal Revenue Service. Instructions for Forms 1099-R and 5498
Several exceptions can wipe out the 10% penalty even under 59½:
- A series of substantially equal periodic payments over your life expectancy
- Separation from service at age 55 or older, for a qualified plan (not an IRA)
- Total and permanent disability, or distributions to a beneficiary after the account holder’s death
- Unreimbursed medical expenses exceeding 7.5% of your adjusted gross income
- Up to $10,000 from an IRA for a qualified first-time home purchase
- Up to $22,000 for losses from a federally declared disaster
If an exception applies but the payer used Code 1, you’ll need to attach Form 5329 to claim it.11Internal Revenue Service. Topic No. 558, Additional Tax on Early Distributions From Retirement Plans People often add the income on an amended return and forget the 5329, and the IRS then assesses the 10% penalty automatically.
First Time Abate
If you filed on time and stayed penalty-free for the prior three tax years, you may qualify for the IRS’s First Time Abate program, which waives certain penalties. Call the number on your notice or send a written request, and the IRS checks your compliance history.12Internal Revenue Service. Administrative Penalty Relief Interest is never waived, so paying fast still matters.
Fixing It Yourself With Form 1040-X
Amending before the IRS contacts you shows good faith and limits penalty exposure. The tool is Form 1040-X, the Amended U.S. Individual Income Tax Return.13Internal Revenue Service. About Form 1040-X, Amended U.S. Individual Income Tax Return
Get a copy of the 1099-R first. Most payers keep them in your online account. If the payer won’t provide one and it’s past the end of February, call the IRS at 800-829-1040; the agency will contact the payer and send you Form 4852 to use as a substitute.14Internal Revenue Service. Form 4852, Substitute for Form W-2 or Form 1099-R Pull your original return as well so you can compare it side-by-side with the 1099-R, and make sure you claim credit for anything withheld in Box 4.
Form 1040-X uses three columns: Column A is the original figures, Column B is the change, Column C is the corrected amounts.15Internal Revenue Service. Instructions for Form 1040-X Update adjusted gross income and total tax to reflect the added distribution. In Part III, write a clear explanation. Something like “Adding $12,000 pension distribution from [Payer Name] reported on Form 1099-R that was omitted from the original return” is enough.
You can file 1040-X electronically for the current year or the two prior tax years. On paper, send it certified mail with return receipt so you have proof of delivery. Processing usually takes 8 to 12 weeks, sometimes up to 16.15Internal Revenue Service. Instructions for Form 1040-X Track it through the IRS “Where’s My Amended Return?” tool.13Internal Revenue Service. About Form 1040-X, Amended U.S. Individual Income Tax Return
Pay whatever you can when you file. Interest and the failure-to-pay penalty keep running until the balance is zero, so paying before the return is even processed limits the damage. The IRS accepts Direct Pay bank transfers, debit and credit cards (with processing fees), same-day wires, and cash at certain retail partners.16Internal Revenue Service. Payments If you can’t pay in full, pay what you can now and set up an installment agreement for the rest.
If a CP2000 Notice Already Arrived
If the IRS beat you to it and the notice is correct, don’t file an amended return. Sign the response form on the notice agreeing to the adjustment and pay the proposed amount.17Internal Revenue Service. Understanding Your CP2000 Series Notice
If you disagree — the distribution was a nontaxable rollover, the amount is wrong, an exception to the 10% penalty applies — complete the response form to that effect and include supporting documents like the actual 1099-R or a rollover confirmation. You can upload the response through the IRS online tool, fax it, or mail it to the address on the notice.17Internal Revenue Service. Understanding Your CP2000 Series Notice If you agree with the CP2000 but also want to claim credits or deductions you missed originally, file a 1040-X with “CP2000” written at the top and send it along with the response form.
Deadline When the Correction Produces a Refund
If the missing 1099-R actually results in a refund — usually because Box 4 withholding exceeds the tax on the distribution — there is a hard deadline. File the amended return within three years from the date you filed the original, or two years from the date you paid the tax, whichever is later.18Internal Revenue Service. Time You Can Claim a Credit or Refund Miss the window and the money stays with the IRS. If the omission means you owe more instead, there’s no deadline on the IRS’s ability to collect — the only clock that matters is the one adding interest and penalties every day you wait.