IRS Form 4810: Prompt Assessment, 18-Month Window, and Exceptions

IRS Form 4810 is a request for prompt assessment that lets the fiduciary of a decedent’s estate or the representative of a dissolving corporation cut the IRS’s window to assess additional tax on specific already-filed returns from three years down to 18 months.¹ The clock starts the day the IRS receives the request, and once it runs out, the agency generally cannot come back for more tax on the returns you listed. For anyone trying to close an estate or wind up a corporation cleanly, that shorter deadline is the whole point.

Who Can File

Ordinary taxpayers cannot use this form to speed up their own audit exposure. Only two filers qualify:²

The executor, administrator, or other fiduciary of a decedent’s estate, for income tax, gift tax, and other qualifying returns filed by the decedent or by the estate during administration.
A corporation that is contemplating dissolution, currently dissolving, or already dissolved, filing through its authorized officer. The dissolution has to be in good faith; a corporation that is merely restructuring or reorganizing does not qualify.

Whoever signs must be legally authorized to act for the estate or corporation. For an estate, that usually means letters testamentary or letters of administration from the probate court. Corporations currently in Chapter 7, 11, or 13 bankruptcy cannot use Form 4810, because the bankruptcy court has jurisdiction over the tax determination.³

Which Returns Qualify

The IRS accepts prompt assessment requests only for these forms:³

Form 1040 (all series), for the decedent or surviving spouse.
Form 1041, for the estate or trust during administration.
Form 1120 (all series except 1120-S), for the dissolving corporation. S-corporation returns are excluded.
Form 709, gift tax returns.
Employment tax returns (940, 941, 943, 944, 945), but only when filed in connection with a corporation that is dissolving or already dissolved.

One exclusion catches many executors off guard. Estate tax returns filed on Form 706 are not eligible. The statute expressly carves out the estate tax imposed under chapter 11 of subtitle B.¹ If your goal is to shorten the audit window on the estate tax itself, Form 4810 will not do it. The standard three-year statute of limitations applies to Form 706, and there is no way to compress it.

What Goes on the Form

The form itself is short, but small errors trigger rejections. You need to provide:⁴

The type of tax (income, gift, employment, or excise). List each type separately.
Each taxable period, with the exact date the corresponding return was filed.
The taxpayer name and SSN or EIN exactly as they appeared on the original returns. Any mismatch with IRS records causes rejection.
For an estate, the decedent’s name, SSN, date of death, and the surviving spouse’s name and SSN if applicable.
Copies of letters testamentary or letters of administration proving your authority.

A point that trips up practitioners: a Power of Attorney on Form 2848 does not substitute for letters testamentary or letters of administration. The IRS treats them as separate documents. A CPA or attorney submitting on behalf of a fiduciary needs both, the POA covering the representative and the court-issued letters covering the fiduciary.³ For dissolving corporations, mark the dissolution checkbox whenever corporate income tax returns are included.

How to File

Two timing rules can invalidate the request. Do not send Form 4810 until every return listed on it has actually been filed; a request covering a return that isn’t in yet is invalid.⁴ And send it by itself. Do not staple it to a return or fold it into other correspondence.²

Mail the form to the IRS service center where the underlying returns were originally filed.⁴ Gift tax returns have a dedicated address regardless of where Form 709 was filed: Internal Revenue Service, Stop 824G, 7940 Kentucky Drive, Florence, KY 41042-2915. IRS-designated private delivery services are an option, but they cannot deliver to P.O. boxes; the current approved list is at irs.gov/PDS.

Use certified mail with return receipt requested. The IRS does not acknowledge receipt of Form 4810, so your mailing receipt is your only proof of the filing date. That date starts the 18-month clock, so keep the signed form, its attachments, and the receipt together.

How the 18-Month Window Works

Once the IRS receives a valid request, it has 18 months to assess additional tax on the returns you listed.¹ If the window closes without action, the agency generally loses the ability to assess a deficiency on those specific returns and tax periods.

The request cannot extend the assessment period beyond what already exists. If the standard three-year statute would run out sooner than the 18 months, the earlier date still controls.² Practically, that means the benefit is largest when you file soon after the returns. Wait two years and you’re only trimming a few months. File within a few months and you cut roughly a year and a half off the exposure.

The shortened window covers only the returns and periods identified on the form. Anything not listed remains under the standard statute, so list every return type and every year you want to close out.

Exceptions That Override the Short Window

Filing Form 4810 does not shut every door. Several statutory exceptions override both the 18-month window and the ordinary three-year period:

Fraud. If the return was false or fraudulent with intent to evade tax, there is no time limit on assessment.¹
No return filed. Form 4810 only works for returns that have actually been submitted. If a required return was never filed, the IRS can assess at any time.
Substantial omission of income. If more than 25 percent of gross income was left off a return, the IRS has six years, not three. Form 4810 does not shorten that extended period.

These exceptions matter most in the estate context, where the decedent cannot explain past filings and the executor may not know whether prior returns were complete. If the IRS finds a substantial omission after the 18-month window closes, the six-year period still applies. Executors who suspect gaps in the decedent’s prior reporting should account for that risk before distributing assets.

Common Reasons the IRS Rejects the Request

Based on internal IRS processing guidance, these errors are the frequent ones:³

Missing letters testamentary, letters of administration, or an equivalent court order. A Power of Attorney alone is not enough.
Taxpayer name or identification number does not match IRS records, often from a slightly different spelling or an outdated EIN.
The form was sent before the underlying return was filed.
The form was bundled with a return or other correspondence rather than sent on its own.
For corporate returns, the dissolution checkbox was not marked.

When the IRS spots an incomplete request, it sends Letter 621C asking for what’s missing. You typically have 60 days to respond. Miss the deadline and the case closes; you would have to start over with a fresh request. Duplicate submissions that add no new information are not processed.

Form 4810 vs. Form 5495

Fiduciaries often confuse these two forms because both help wrap up a decedent’s tax affairs, but they solve different problems. Form 4810 shortens the time the IRS has to assess additional tax on specific returns. Form 5495 discharges the executor or fiduciary from personal liability for the decedent’s unpaid income, gift, and estate taxes.⁵

The distinction matters. Form 4810 protects the estate; once the 18 months close, the IRS generally cannot pursue more tax on the listed returns. It does nothing for you personally. Distribute assets to heirs and then have the IRS come back with a tax bill, and you can be on the hook as the fiduciary. Form 5495 addresses that. After the IRS receives the request, the executor is discharged from personal liability nine months later (six months for trust fiduciaries), or upon paying whatever the IRS determines is owed, whichever comes first.⁶

Many estate practitioners file both. Form 4810 compresses the audit window for the estate’s returns. Form 5495 covers the executor personally. Neither one substitutes for the other, and neglecting either can leave a gap that surfaces after assets have been distributed.

1
Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection
2
eCFR. 26 CFR 301.6501(d)-1 – Request for Prompt Assessment
3
Internal Revenue Service. 4.19.12 Classification Support
4
Internal Revenue Service. Form 4810 – Request for Prompt Assessment Under Internal Revenue Code Section 6501(d)
5
Internal Revenue Service. About Form 5495, Request for Discharge from Personal Liability Under IR Code Sec 2204 or 6905
6
Office of the Law Revision Counsel. 26 USC 6905 – Discharge of Executor From Personal Liability for Decedents Income and Gift Taxes