§6664. Definitions and special rules

(a) Underpayment

For purposes of this part, the term "underpayment" means the amount by which any tax imposed by this title exceeds the excess of-

(1) the sum of-

(A) the amount shown as the tax by the taxpayer on his return, plus

(B) amounts not so shown previously assessed (or collected without assessment), over

(2) the amount of rebates made.

For purposes of paragraph (2), the term "rebate" means so much of an abatement, credit, refund, or other repayment, as was made on the ground that the tax imposed was less than the excess of the amount specified in paragraph (1) over the rebates previously made.

(b) Penalties applicable only where return filed

The penalties provided in this part shall apply only in cases where a return of tax is filed (other than a return prepared by the Secretary under the authority of section 6020(b)).

(c) Reasonable cause exception

(1) In general

No penalty shall be imposed under this part with respect to any portion of an underpayment if it is shown that there was a reasonable cause for such portion and that the taxpayer acted in good faith with respect to such portion.

(2) Special rule for certain valuation overstatements

In the case of any underpayment attributable to a substantial or gross valuation overstatement under chapter 1 with respect to charitable deduction property, paragraph (1) shall not apply unless-

(A) the claimed value of the property was based on a qualified appraisal made by a qualified appraiser, and

(B) in addition to obtaining such appraisal, the taxpayer made a good faith investigation of the value of the contributed property.

(3) Definitions

For purposes of this subsection-

(A) Charitable deduction property

The term "charitable deduction property" means any property contributed by the taxpayer in a contribution for which a deduction was claimed under section 170. For purposes of paragraph (2), such term shall not include any securities for which (as of the date of the contribution) market quotations are readily available on an established securities market.

(B) Qualified appraiser

The term "qualified appraiser" means any appraiser meeting the requirements of the regulations prescribed under section 170(a)(1).

(C) Qualified appraisal

The term "qualified appraisal" means any appraisal meeting the requirements of the regulations prescribed under section 170(a)(1).

(Added Pub. L. 101–239, title VII, §7721(a), Dec. 19, 1989, 103 Stat. 2398 .)

Section Referred to in Other Sections

This section is referred to in section 6662 of this title.