If you do not file a required return, the IRS can file one for you. Under §6020(b), when a person fails to make a required return — or files a false or fraudulent one — the Secretary may make the return “from his own knowledge and from such information as he can obtain through testimony or otherwise,” and a return made and subscribed that way is “prima facie good and sufficient for all legal purposes.” That document is a substitute for return, or SFR. It is built only from income the IRS can see, it almost always overstates what you owe, and it is fully enforceable once assessed. This page covers how an SFR is built, the notice ladder it travels, and the fix: a real, signed, original return filed to the right unit — never an amended return.
General information, not tax or legal advice. SFR assessments carry a hard 90-day Tax Court deadline on the CP3219N notice; if yours is running, treat the date on the notice as controlling.
An SFR is prepared under the examination procedures in IRM 4.12.1 when a liable taxpayer, after due notice, still has not filed. The raw material is information reporting only: the W-2s, 1099s and other information returns filed under your Social Security number. What the IRS cannot see, the SFR does not include. The IRS’s own past-due page warns that the substitute return “might not give you credit for deductions and exemptions you may be entitled to receive,” and standard SFR practice compounds that: the least favourable filing status (single, or married filing separately), the standard deduction only, and no credits, deductions or cost basis that are not visible on an information return. Sell stock and the SFR commonly taxes the full proceeds as gain, because the IRS received the proceeds figure but not your basis. That is why an SFR balance is typically far higher than the real liability — it is a worst-case reconstruction, not an audit of your actual return.
| Rung | What it is | Your window | What happens if you do nothing |
|---|---|---|---|
| CP2566 | The SFR proposal: the IRS shows the return it intends to file from its records | 30 days to file your own return, explain why you are not liable, or sign the consent to assessment | The process moves to the statutory notice |
| CP3219N | The 90-day letter (notice of deficiency) proposing assessment of the SFR tax | 90 days from the notice date — 150 days if addressed outside the United States — to file the past-due return or petition the U.S. Tax Court; no extension can be requested | The IRS assesses the proposed tax and collection begins |
| Assessment | The SFR tax posts to your account | — | The balance is enforceable: liens, levies, offsets; your remedy shifts to reconsideration (below) |
Deficiency procedures apply to an SFR just as they do to an examined return: the tax is assessed only after the notice of deficiency gives you your Tax Court chance. That makes the CP3219N window the most important 90 days in the process — it is the last point where the fix is cheap.
Get this part exactly right, because much of the advice online gets it wrong. An SFR does not start the assessment limitations period. Section 6501(b)(3) states it directly: execution of a return by the Secretary under §6020(b) “shall not start the running of the period of limitations on assessment and collection.” IRM 25.6.1.9.4.5 separates the two clocks: an SFR assessment does start the §6502 collection period, running from the assessment date — but it does not start the §6501 assessment period. The practical consequences:
The fix is a real return — a signed original Form 1040 for that year, with the correct filing status, deductions, credits and basis. Two rules govern it. First, never file Form 1040-X against an SFR: an SFR is not your return, so there is nothing of yours to “amend”; the IRS needs the original return itself. Second, send it to the address or unit shown on the CP2566 or CP3219N, not to the normal filing address — the SFR file lives with that unit, and a return mailed to the regular service center can sit unconnected while the assessment posts. The IRS states it will generally adjust the account to the correct figures when your own return is filed. Filing inside the CP3219N window also preserves the alternative: petitioning the Tax Court within the same 90 days.
If the window closed and the SFR tax has already assessed, the same original return still works — but it travels a different road. It is processed as a request for audit reconsideration (IRM 4.13.1; ASFR reconsideration procedures at IRM 5.1.15.4 for collection-secured returns): you submit the return and documentation, and the IRS re-examines whether the assessed figure should be reduced. Reconsideration is discretionary and slower than acting on the notice, and collection continues meanwhile — the assessment is legally live while your return is considered. That asymmetry is the argument for treating the CP3219N as a hard deadline.
One related consequence, in a line because its teaching lives elsewhere: an SFR-assessed year is treated as unfiled for bankruptcy discharge purposes — see which taxes can be discharged in bankruptcy. The failure-to-file penalty on the SFR balance is computed on the shipped 2.5 page, not here.
How do I know if the IRS filed a substitute for return for me? Watch the mail and your account. The process announces itself: a CP2566 proposal first, then a CP3219N 90-day letter proposing the assessment. Your tax account transcript will also show an assessment for a year you never filed. Either is your signal that the year is on the SFR track, not the voluntary track on the unfiled tax returns hub.
Can I file my own return after the IRS files an SFR? Yes — that is the fix. File a signed original return for the year, with your real status, deductions and credits, and send it to the address on the CP2566 or CP3219N. Before assessment, the IRS will generally adjust the account to your return’s figures; after assessment, the return is handled as an audit reconsideration request.
What happens if I ignore the CP3219N? The 90 days (150 if the notice is addressed abroad) expire with no extension available, the IRS assesses the proposed SFR tax, and the balance becomes collectible — liens, levies and refund offsets follow, and you lose the pre-assessment Tax Court route. Your remaining remedy is audit reconsideration while collection continues.
Why is my SFR balance so much higher than what I actually owe? Because the SFR is built only from income the IRS can see, at the least favourable filing status, with the standard deduction only — no credits, no extra deductions, and no cost basis on asset sales. It is a worst-case reconstruction designed to be replaced by your real return, not a measurement of your actual liability.
Do I file a 1040-X to fix a substitute for return? No. Form 1040-X amends your return, and an SFR is the IRS’s return, not yours. File the signed original Form 1040 for that year instead, marked and mailed to the SFR unit on your notice.
General information, not tax or legal advice. Sources: 26 U.S.C. §§6020(b), 6213(a), 6501(b)(3); IRM 4.12.1, 4.13.1, 5.1.15.4, 25.6.1.9.4.5; IRS, “Filing past due tax returns” and “Understanding your CP3219N notice.” Currency verified 2026-10-23.