In the case of any adjustment which reallocates the distributive share of any item from one partner to another, such adjustment shall be taken into account by disregarding so much of such adjustment as results in a decrease in the amount of the imputed underpayment.
The Secretary shall establish procedures under which the imputed underpayment amount may be modified consistent with the requirements of this subsection.
In the case of any adjustment which reallocates the distributive share of any item from one partner to another, this paragraph shall apply with respect to any such partner only if the requirements of subparagraph (A) or (B) are satisfied with respect to all partners affected by such adjustment.
The adjustments to the tax attributes of any partner provided for in subparagraph (A)(ii) or (B)(ii) shall be binding with respect to the taxable year of the partner which includes the end of the reviewed year of the partnership and any taxable years for which any tax attribute is affected by such adjustment. Any failure to so treat any such tax attribute shall be treated for purposes of this title in the same manner as a failure to treat a partnership-related item in a manner which is consistent with the treatment of such item on the partnership return within the meaning of section 6222.
For purposes of clause (i), an S corporation and its shareholders shall be treated in the same manner as a partnership and its partners.
An administrative adjustment request under section 6227 and a partnership adjustment tracking report under section 6226(b)(4)(A) shall not be treated as a return for purposes of this paragraph.
Except as provided in clause (ii), the portion of the imputed underpayment to which the lower rate applies with respect to a partner under subparagraph (A) shall be determined by reference to the partners’ distributive share of items to which the imputed underpayment relates.
If the imputed underpayment is attributable to the adjustment of more than 1 item, and any partner’s distributive share of such items is not the same with respect to all such items, then the portion of the imputed underpayment to which the lower rate applies with respect to a partner under subparagraph (A) shall be determined by reference to the amount which would have been the partner’s distributive share of net gain or loss if the partnership had sold all of its assets at their fair market value as of the close of the reviewed year of the partnership.
The Secretary may by regulations or guidance provide for additional procedures to modify imputed underpayment amounts on the basis of such other factors as the Secretary determines are necessary or appropriate to carry out the purposes of this subsection.
Anything required to be filed or submitted under this subsection shall be submitted to the Secretary not later than the close of the 270-day period beginning on the date on which the notice of a proposed partnership adjustment is mailed under section 6231 unless such period is extended with the consent of the Secretary.
Any modification of the imputed underpayment amount under this subsection shall be made only upon approval of such modification by the Secretary.