26 U.S.C. § 6663
Section 6663 · Imposition of fraud penalty
Amended 1 time on record
Applied in 79 court decisions — leading case Pittman v. Commissioner (1996)
Most recently applied in United States v. Isac Schwarzbaum (January 2025)
How often courts cite this section
Court decisions citing this, by year.Markers show enactment, consequential amendments, and circuit splits over this section — watch for a citation surge after a change or a disagreement. The dip in the last several years is a data-coverage gap, not a real trend — our corpus holds fewer opinions from the most recent years, so recent citations are undercounted.
If any part of any underpayment of tax required to be shown on a return is due to fraud, there shall be added to the tax an amount equal to 75 percent of the portion of the underpayment which is attributable to fraud.
If the Secretary establishes that any portion of an underpayment is attributable to fraud, the entire underpayment shall be treated as attributable to fraud, except with respect to any portion of the underpayment which the taxpayer establishes (by a preponderance of the evidence) is not attributable to fraud.
In the case of a joint return, this section shall not apply with respect to a spouse unless some part of the underpayment is due to the fraud of such spouse.