§ 992. Addition to tax in the case of valuation understatement. In the
case of any underpayment of a tax imposed by this article which is
attributable to a valuation understatement, there shall be added to the
tax an amount equal to the applicable percentage of the underpayment so
attributed.

(a) For purposes of this section, the applicable percentage shall be
determined under the following table:

If the valuation claimed is

the following percent of the The applicable

correct valuation: percentage is:

fifty percent or more but

not more than sixty-six

and two-thirds percent .................... ten

forty percent or more but

less than fifty percent ................... twenty

less than forty percent ................... thirty

(b) For purposes of this section, there is a valuation understatement
if the claimed value of any property is sixty-six and two-thirds percent
or less of the amount determined to be the correct amount of such
valuation.

(c) This section shall not apply if the underpayment is less than one
thousand dollars with respect to the estate of the decedent.

(d) The commissioner may waive all or any part of the addition to tax
provided by this section on showing by the executor that there was a
reasonable basis for the claimed valuation and that such claim was made
in good faith.