26 U.S.C. § 6700: Promoting abusive tax shelters, etc.

a partnership or other entity, any investment plan or arrangement, or any other plan or arrangement, or participates (directly or indirectly) in the sale of any interest in an entity or plan or arrangement referred to in subparagraph (A), and a statement with respect to the allowability of any deduction or credit, the excludability of any income, or the securing of any other tax benefit by reason of holding an interest in the entity or participating in the plan or arrangement which the person knows or has reason to know is false or fraudulent as to any material matter, or a gross valuation overstatement as to any material matter, the value so stated exceeds 200 percent of the amount determined to be the correct valuation, and the value of such property or services is directly related to the amount of any deduction or credit allowable under chapter 1 to any participant. The Secretary may waive all or any part of the penalty provided by subsection (a) with respect to any gross valuation overstatement on a showing that there was a reasonable basis for the valuation and that such valuation was made in good faith. The penalty imposed by this section shall be in addition to any other penalty provided by law.