Failure-to-file penalty under IRC 6651(a)(1): computation and relief

The rule

IRC 6651(a)(1) adds to the tax “5 percent of the amount of such tax if the failure is for not more than 1 month, with an additional 5 percent for each additional month or fraction thereof during which such failure continues, not exceeding 25 percent in the aggregate”, unless the failure is due to reasonable cause and not willful neglect. The due date is determined with regard to any extension. Because of the cap, the penalty “is not charged for more than 5 months” (IRM 20.1.2.3.7.1).

The penalty applies to income, employment, excise, gift and estate tax returns. Partnership and S corporation information returns have their own per-partner and per-shareholder penalties; see IRC 6698 and IRC 6699.

Counting the months

The penalty period begins on the day after the latest of the normal due date, the extended due date, a disaster due date under IRC 7508A, or a combat zone due date under IRC 7508. Each penalty month ends on the day of the month matching the due date. If the due date is the last day of a month, each new month starts on the first of the next month; if the day does not exist in February, the new month starts March 1 (IRM 20.1.2.3.7.1).

A return due April 15 and filed July 13 is three months late: it was not filed by April 15, May 15 or June 15.

The amount subject to the penalty

The base is the tax required to be shown on the return, reduced by amounts paid on or before the payment due date (without regard to extensions) and by credits that may be claimed on the return (IRC 6651(b)(1); IRM 20.1.2.3.7.2). Payments made after the payment due date do not reduce the base. That is why a client who files late but paid in full by April 15 owes no failure-to-file penalty at all: there is no net amount due.

Because the base is tax required to be shown, an audit deficiency increases the failure-to-file penalty retroactively (see below).

Coordination with failure to pay

Under IRC 6651(c)(1), the failure-to-file penalty is reduced by the failure-to-pay penalty under 6651(a)(2) for any month both apply. The IRM's worked example (IRM 20.1.2.3.8.7.1):

The combined rate for a month when both penalties run is therefore 5 percent, not 5.5 percent. After the fifth month, failure to file stops and failure to pay continues alone; see the failure-to-pay penalty. The penalty and interest calculator applies the same coordination.

The minimum penalty

For an income tax return more than 60 days late (counting extensions), the penalty cannot be less than the lesser of a dollar floor or 100 percent of the tax required to be shown (IRC 6651(a), last sentence). The floor is inflation adjusted under IRC 6651(j). The IRM table:

Rev. Proc. 2024-40 sets the $525 figure for returns required to be filed in 2026, and Rev. Proc. 2025-32 sets $535 for returns required to be filed in 2027. The minimum applies only to income tax returns, not to employment, excise, gift or estate tax returns, and not to an individual who had to file only to report self-employment tax, uncollected social security tax, household employment tax or certain Form 5329 excise taxes (IRM 20.1.2.3.7.4). The minimum survives the 6651(c)(1) offset.

The IRM's minimum-penalty example shows how small balances behave: a 2021 return showing $148 tax, paid with the return, received 61 days after April 15, 2022. The computed penalty would be $13.32, but the minimum is the lesser of $435 or the $148 tax, so the penalty is $148 (IRM 20.1.2.3.8.7.4).

Timely mailing, e-file and extensions

Under IRC 7502, a return received late is treated as filed on the postmark date if it was mailed in the United States by the due date, properly addressed, with enough postage, through USPS or a designated private delivery service. “Properly addressed” means an IRS office listed in the instructions or on IRS.gov (IRM 20.1.2.2.1). For e-filed returns, a timely electronic postmark counts, and a rejected e-file is still timely “if they are mailed (or re-transmitted) within 10 days of initial notification of rejection.”

An extension extends the time to file, not to pay. Employment tax returns cannot be extended, but no late filing penalty is asserted if 100 percent of the tax was deposited by the due date (IRM 20.1.2.2.3.1). When an extension was filed but does not show on the account, the IRM has procedures to input it, and an extension that should have posted is an IRS error, not a reasonable cause case.

Deficiencies and substitute returns

A deficiency raises the base. In the IRM's continuation of the example above, a $1,000 deficiency increases the tax required to be shown to $6,000, so the penalty becomes 3 months x 5% x $6,000 minus $65, or $835; the increase over the amount assessed goes in the notice of deficiency (IRM 20.1.2.3.8.7.2). The IRM warns examiners not to multiply the deficiency by 5 percent per month when payments were made after the due date, because that gives the wrong answer.

Only the part of the penalty attributable to a deficiency goes through deficiency procedures. In the IRM 20.1.1.4.2 example, a return one month late reporting $4,000 tax and a $1,000 deficiency produce a $250 total penalty; $50 goes in the notice of deficiency and the remaining $200 is assessed immediately.

For a return the IRS prepares under IRC 6020(b), IRC 6651(g) says it is disregarded in computing the failure-to-file addition but treated as the taxpayer's return for failure to pay.

Fraudulent failure to file: IRC 6651(f)

If the failure is fraudulent, the rate becomes 15 percent per month and the cap 75 percent. The IRM calls it “a counterpart of the civil fraud penalty under IRC 6663”, says “The burden of proof is on the government”, and requires “clear and convincing evidence the failure to file was done with the intent to evade taxes” (IRM 20.1.2.3.7.5). Factors include a refusal or inability to explain the failure, a history of not filing with an apparent ability to pay, concealing assets, and unusual cash dealings; awareness of the filing requirement should not be the sole factor. All proposals require Area Counsel approval, and although IRC 6751(b)(2) excepts IRC 6651, the IRS requires written managerial approval for 6651(f) as a matter of policy. The IRM says the penalty generally should not be proposed if the late return showed a refund. See the civil fraud penalty.

Relief

• IRS error. Timely mailed returns, unposted extensions and misapplied payments are corrected and the penalty reversed, not abated for reasonable cause.
• First Time Abate. Available for 6651(a)(1) if the three prior years are clean; see First Time Abate.
• Reasonable cause. The penalty “can be abated for reasonable cause regardless of payment of tax”, but a prolonged failure beyond the effect of the cause, or failure to file other returns, may show willful neglect (IRM 20.1.2.2.4.1). Reliance on a preparer or agent to file does not qualify: in United States v. Boyle, 469 U.S. 241 (1985), the Supreme Court held that an executor who left the filing to his attorney had no reasonable cause for the late estate tax return, because meeting a known deadline needs no special training, while leaving open relief for reliance on substantive advice that no return was due. See reasonable cause for Boyle and the IRM standards.
• Disaster and combat zone. Postponed due dates move the start of the penalty period; see disaster postponements.

Interest on the failure-to-file penalty runs from the return due date including extensions, not from notice and demand (IRM 20.1.2.2.4). Supervisory approval under IRC 6751(b) is not required for 6651(a) penalties.

Questions practitioners ask