26 U.S.C. § 6233: Interest and penalties

interest shall be computed under paragraph (2), and the partnership shall be liable for any penalty, addition to tax, or additional amount as provided in paragraph (3). The interest computed under this paragraph with respect to any partnership adjustment is the interest which would be determined under chapter 67 for the period beginning on the day after the return due date for the reviewed year and ending on the return due date for the adjustment year (or, if earlier, the date payment of the imputed underpayment is made). Proper adjustments in the amount determined under the preceding sentence shall be made for adjustments required for partnership taxable years after the reviewed year and before the adjustment year by reason of such partnership adjustment. Any penalty, addition to tax, or additional amount shall be determined at the partnership level as if such partnership had been an individual subject to tax under chapter 1 for the reviewed year and the imputed underpayment were an actual underpayment (or understatement) for such year. for interest as determined under paragraph (2), and for any penalty, addition to tax, or additional amount as determined under paragraph (3). Interest determined under this paragraph is the interest that would be determined by treating the imputed underpayment as an underpayment of tax imposed in the adjustment year. by applying section 6651(a)(2) to such failure to pay, and by treating the imputed underpayment as an underpayment of tax for purposes of part II of subchapter A of chapter 68. For rules allowing deposits to suspend running of interest on potential underpayments, see section 6603.