I.R.C. § 6663(a) Imposition Of Penalty
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.
I.R.C. § 6663(b) Determination Of Portion 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
I.R.C. § 6663(c) Special Rule For Joint Returns
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.
(Added Pub. L. 101-239, title VII, Sec. 7721(a), Dec.
19, 1989, 103 Stat. 2397.)