of this subsection, the amount of any deficiency which is prorated to installments payable under section 6168 shall be treated as an amount of tax payable in installments under such section. . 215. Waiver of penalty for underpayment of estimated tax Section 6654(e)(3) of the Internal Revenue Code of 1986 is amended by adding at the end the following new subparagraph: (C) Capital gains payable upon death No addition to tax shall be imposed under subsection (a) with respect to any underpayment if the taxpayer died during the taxable year and the Secretary determines that the amount of the underpayment is due to capital gains that were realized by reason of section 1261. . 216. Effective date Except as otherwise provided, the amendments made by this subtitle shall apply to transfers after December 31, 2018, in taxable years beginning after such date.