(a) Interest and penalties with respect to failure to pay imputed underpayment on the date prescribed. In the case of any failure to pay an imputed underpayment on the date prescribed for such payment (as described in § 301.6232-1(b)), a partnership is liable for—

(1) Interest as determined under paragraph (c) of this section; and

(2) Any penalty, addition to tax, or additional amount as determined under paragraph (d) of this section.

(b) Imputed underpayments to which this section applies. This section applies to the portion of an imputed underpayment determined by the Internal Revenue Service (IRS) under section 6225(a)(1), or an imputed underpayment resulting from adjustments requested by a partnership in an administrative adjustment request under section 6227, that is not paid by the date prescribed for payment under § 301.6232-1(b).

(c) Interest. Interest determined under this paragraph (c) is the interest that would be imposed under chapter 67 of the Internal Revenue Code (Code) by treating any unpaid amount of the imputed underpayment as an underpayment of tax imposed for the adjustment year (as defined in § 301.6241-1(a)(1)). The interest under this paragraph (c) begins on the date prescribed for payment (as described in § 301.6232-1(b)) and ends on the date payment of the imputed underpayment is made.

(d) Penalties. If a partnership fails to pay an imputed underpayment by the date prescribed for payment (as described in § 301.6232-1(b)), section 6651(a)(2) applies to such failure, and any unpaid amount of the imputed underpayment is treated as if it were an underpayment of tax for purposes of part II of subchapter A of chapter 68 of the Code. For purposes of this section, the penalty under 6651(a)(2) is applied by treating the unpaid amount of the imputed underpayment as the unpaid amount shown as tax on a return required under subchapter A of chapter 61 of the Code.

(e) Applicability date—(1) In general. Except as provided in paragraph (e)(2) of this section, this section applies to partnership taxable years beginning after December 31, 2017, and ending after August 12, 2018.

(2) Election under § 301.9100-22 in effect. This section applies to any partnership taxable year beginning after November 2, 2015, and before January 1, 2018, for which a valid election under § 301.9100-22 is in effect.