TREASURY REGULATIONS

(a) In general. An imputed underpayment determined under subchapter C of chapter 63 of the Internal Revenue Code (Code) is assessed and collected in the same manner as if the imputed underpayment were a tax imposed by subtitle A of the Code for the adjustment year (as defined in § 301.6241-1(a)(1)) except that the deficiency procedures under subchapter B of chapter 63 of the Code do not apply to an assessment of an imputed underpayment. Accordingly, no notice under section 6212 is required for, and the restrictions under section 6213 do not apply to, the assessment of any imputed underpayment. See paragraph (c) of this section for limitations on assessment and paragraph (d) of this section for exceptions to restrictions on adjustments.

(b) Payment of the imputed underpayment. Upon receipt of notice and demand from the Internal Revenue Service (IRS), an imputed underpayment must be paid by the partnership at the place and time stated in the notice. In the case of an adjustment requested in an administrative adjustment request (AAR) under section 6227(b)(1) that is taken into account by the partnership under § 301.6227-2(b), payment of the imputed underpayment is due on the date the AAR is filed. The IRS may assess the amount of the imputed underpayment reflected on the AAR on the date the AAR is filed. For interest with respect to an imputed underpayment, see § 301.6233(a)-1(b).

(c) Limitation on assessment—(1) In general. Except as otherwise provided by this section or subtitle F of the Code (except for subchapter B of chapter 63), no assessment of an imputed underpayment may be made (and no levy or proceeding in any court for the collection of an imputed underpayment may be made, begun, or prosecuted) before—

(i) The close of the 90th day after the day on which a notice of a final partnership adjustment (FPA) under section 6231(a)(3) was mailed; and

(ii) If a petition for readjustment is filed under section 6234 with respect to such FPA, the decision of the court has become final.

(2) Specified similar amount. The limitations under paragraph (c)(1) of this section do not apply in the case of a specified similar amount as defined in section 6232(f)(2).

(d) Exceptions to restrictions on adjustments and assessments—(1) Adjustments treated as mathematical or clerical errors—(i) In general. A notice to a partnership that, on account of a mathematical or clerical error appearing on the partnership return or as a result of a failure by a partnership-partner (as defined in § 301.6241-1(a)(7)) to comply with section 6222(a), the IRS has adjusted or will adjust partnership-related items (as defined in § 301.6241-1(a)(6)(ii)) to correct the error or to make the items consistent under section 6222(a) and has assessed or will assess any imputed underpayment (determined in accordance with § 301.6225-1) resulting from the adjustment is not considered an FPA under section 6231(a)(3). A petition for readjustment under section 6234 may not be filed with respect to such notice. The limitations under section 6232(b) and paragraph (c) of this section do not apply to an assessment under this paragraph (d)(1)(i). For the definition of mathematical or clerical error generally, see section 6213(g)(2). For application of mathematical or clerical error in the case of inconsistent treatment by a partner that fails to give notice, see § 301.6222-1(b).

(ii) Request for abatement—(A) In general. Except as provided in paragraph (d)(1)(ii)(B) of this section, a partnership that is mailed a notice described in paragraph (d)(1)(i) of this section may file with the IRS, within 60 days after the date of such notice, a request for abatement of any assessment of an imputed underpayment specified in such notice. Upon receipt of the request, the IRS must abate the assessment. Any subsequent assessment of an imputed underpayment with respect to which abatement was made is subject to the provisions of subchapter C of chapter 63 of the Code, including the limitations under paragraph (c) of this section.

(B) Adjustments with respect to inconsistent treatment by a partnership-partner. If an adjustment that is the subject of a notice described in paragraph (d)(1)(i) of this section is due to the failure of a partnership-partner to comply with section 6222(a), paragraph (d)(1)(ii)(A) of this section does not apply, and abatement of any assessment specified in such notice is not available. However, prior to assessment, a partnership-partner that has failed to comply with section 6222(a) may correct the inconsistency by filing an administrative adjustment request in accordance with section 6227 or filing an amended partnership return and furnishing amended statements, as appropriate.

(iii) Partnerships that have an election under section 6221(b) in effect. In the case of a partnership-partner that has an election under section 6221(b) in effect for the reviewed year (as defined in § 301.6241-1(a)(8)), any tax resulting from an adjustment due to the partnership-partner's failure to comply with section 6222(a) may be assessed with respect to the reviewed year partners (as defined in § 301.6241-1(a)(9)) of the partnership-partner (or indirect partners of the partnership-partner, as defined in § 301.6241-1(a)(4)). Such tax may be assessed in the same manner as if the tax were on account of a mathematical or clerical error appearing on the reviewed year partner's or indirect partner's return, except that the procedures under section 6213(b)(2) for requesting an abatement of such assessment do not apply.

(2) Partnership may waive limitations. A partnership may at any time by a signed notice in writing filed with the IRS waive the limitations under paragraph (c) of this section (whether or not an FPA under section 6231(a)(3) has been mailed by the IRS at the time of the waiver).

(e) Limit on amount of imputed underpayment where no proceeding is begun. If no proceeding under section 6234 is begun with respect to an FPA under section 6231(a)(3) before the close of the 90th day after the day on which such FPA was mailed, the amount for which the partnership is liable under section 6225 with respect to such FPA cannot exceed the amount determined in such FPA.

(f) Applicability date—(1) In general. Except as provided in paragraph (f)(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.