Reg. § 301.6235-1 Period of limitations on making adjustments.
(a) In general Except as provided in section , section , or of this section (regarding extensions), no partnership adjustment (as defined in ) for any partnership taxable year may be made after the later of the date that is—
(1) 3 years after the latest of—
(i) The date on which the partnership return for such taxable year was filed;
(ii) The return due date (as defined in section ) for the taxable year; or
(iii) The date on which the partnership filed an administrative adjustment request with respect to such taxable year under section ;
(2) The date described in of this section with respect to a request for modification; or
(3) The date described in of this section with respect to a notice of proposed partnership adjustment.
(b) Modification requested under section 6225(c)
(1) In general For purposes of of this section, in the case of any request for modification of any imputed underpayment under section , the date by which the Internal Revenue Service (IRS) may make a partnership adjustment is the date that is 270 days (plus the number of days of an extension of the period for requesting modification (as described in ) agreed to by the IRS under section and ) after the date on which everything required to be submitted to the IRS pursuant to section is so submitted.
(2) Date on which everything is required to be submitted
(i) In general For purposes of of this section, the date on which everything required to be submitted to the IRS pursuant to section is so submitted is the earlier of—
(A) The date the period for requesting modification ends (including extensions) as described in and ; or
(B) The date the period for requesting modification expires as a result of a waiver of the prohibition on mailing a notice of final partnership adjustment (FPA) under . See .
(ii) Incomplete submission has no effect A determination by the IRS that the information submitted as part of a request for modification is incomplete has no effect on the applicability of of this section.
(c) Notice of proposed partnership adjustment For purposes of of this section, the date by which the IRS may make a partnership adjustment is the date that is 330 days (plus the number of days of an extension of the modification period (as described in ) agreed to by the IRS under section and ) after the date the last notice of proposed partnership adjustment (NOPPA) under section is mailed, regardless of whether modification is requested by the partnership under section .
(d) Extension by agreement The periods described in , , and of this section (including any extension of those periods pursuant to this ) may be extended by an agreement, in writing, entered into by the partnership and the IRS before the expiration of such period.
(e) Examples The following examples illustrate the rules of this section. For purposes of these examples, each partnership has a calendar taxable year.
(1) Example 1 Partnership timely files its partnership return for the 2020 taxable year on March 1, 2021. On September 1, 2023, Partnership files an administrative adjustment request (AAR) under section with respect to its 2020 taxable year. As of September 1, 2023, the IRS has not initiated an administrative proceeding under subchapter C of chapter 63 of the Internal Revenue Code with respect to Partnership's 2020 taxable year. Therefore, as of September 1, 2023, under of this section, the period for making partnership adjustments with respect to Partnership's 2020 taxable year expires on September 1, 2026.
(2) Example 2 Partnership timely files its partnership return for the 2020 taxable year on the due date, March 15, 2021. On February 1, 2023, the IRS mails to Partnership and the partnership representative of Partnership (PR) a notice of administrative proceeding under section with respect to Partnership's 2020 taxable year. Assuming no AAR has been filed with respect to Partnership's 2020 taxable year and the IRS has not yet mailed a NOPPA under section with respect to Partnership's 2020 taxable year, the period for making partnership adjustments for Partnership's 2020 taxable year expires on the date determined under of this section, March 15, 2024.
(3) Example 3 The facts are the same as in of this section, except that on June 1, 2023, pursuant to of this section, PR signs an agreement extending the period for making partnership adjustments under section for Partnership's 2020 taxable year to December 31, 2025. In addition, on June 2, 2025, the IRS mails to Partnership and PR a timely NOPPA under section . Pursuant to , the period for requesting modification expires on February 27, 2026 (270 days after June 2, 2025, the date the NOPPA is mailed), but PR does not submit a request for modification on or before this date. Under of this section, the date for purposes of of this section is April 28, 2026, the date that is 330 days from the mailing of the NOPPA. Because April 28, 2026 is later than the date under of this section (December 31, 2025, as extended under of this section), and because no modification was requested, of this section is not applicable, April 28, 2026 is the date on which the period for making partnership adjustments expires under section .
(4) Example 4 The facts are the same as in of this section, except that PR notifies the IRS that Partnership will be requesting modification. On January 5, 2026, PR and the IRS agree to extend the period for requesting modification pursuant to section and for 45 days—from February 27, 2026 to April 13, 2026. PR submits the request for modification to the IRS on April 13, 2026. Therefore, the date determined under of this section is February 22, 2027, which is 270 days after the date everything required to be submitted was so submitted pursuant to of this section plus the additional 45-day extension of the period for requesting modification agreed to by PR and the IRS. Because February 22, 2027 is later than the date under of this section (December 31, 2025, as extended under of this section) and the date under of this section (June 12, 2026, which is 330 days from the date the NOPPA was mailed plus the 45-day extension under section ), February 22, 2027 is the date on which the period for making partnership adjustments expires under section .
(5) Example 5 The facts are the same as in of this section, except that PR does not request an extension of the period for requesting modification. On February 1, 2026, PR submits a request for modification and PR, and the IRS agree in writing to waive the prohibition on mailing an FPA pursuant to . Pursuant to , the period for requesting modification expires as of February 1, 2026, rather than February 27, 2026. Accordingly, under of this section, the date on which everything required to be submitted pursuant to section is so submitted is February 1, 2026, and the 270-day period described in of this section begins to run on that date. Therefore, the date for purposes of of this section is October 29, 2026, which is 270 days after February 1, 2026, the date on which everything required to be submitted under section is so submitted. Because October 29, 2026 is later than the date under of this section (December 31, 2025, as extended under of this section) and the date under of this section (April 28, 2026), October 29, 2026 is the date on which the period for making partnership adjustments expires under section .
(6) Example 6 The facts are the same as in of this section, except PR completes its submission of information to support a request for modification on July 1, 2025, but does not execute a waiver pursuant to . Therefore, pursuant to of this section, February 27, 2026, the date the period requesting modification expires, is the date on which everything required to be submitted pursuant to section is so submitted. As a result, the 270-day period described in of this section expires on November 24, 2026. Because November 24, 2026 is later than the date under of this section (December 31, 2025, as extended under of this section) and the date under of this section (April 28, 2026), November 24, 2026 is the date on which the period for making partnership adjustments expires under section .
(f) Applicability date
(1) In general Except as provided in 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 is in effect.
[T.D. 9844, 84 FR 6566, Feb. 27, 2019]