Look-back Step Three: Calculation of interest on underpayment or overpayment

Look-back Step Three: Calculation of interest on underpayment or overpayment -
(i) In general. After determining a hypothetical underpayment or overpayment of tax for each redetermination year, the taxpayer must determine the interest charged or credited on each of these amounts. Interest on the amount determined under Step Two is determined by applying the overpayment rate designated under section 6621, compounded daily. In general, the time period over which interest is charged on hypothetical underpayments or credited on hypothetical overpayments begins at the due date (not including extensions) of the return for the redetermination year for which the hypothetical underpayment or overpayment determined in Step Two is computed. This time period generally ends on the earlier of:
(A) The due date (not including extensions) of the return for the filing year, and
(B) The date both
(1) The income tax return for the filing year is filed, and
(2) The tax for that year has been paid in full. If a taxpayer uses the simplified marginal impact method contained in paragraph (d), the remainder of this paragraph (c)(4) does not apply.
(ii) Changes in the amount of a loss or credit carryback or carryover. The time period for determining interest may be different in cases involving loss or credit carrybacks or carryovers in order to properly reflect the time period during which the taxpayer (in the case of an underpayment) or the Government (in the case of an overpayment) had the use of the amount determined to be a hypothetical underpayment or overpayment. Thus, if a reallocation of contract income under Step One results in an increase or decrease to a net operating loss carryback (but not a carryforward), the interest due or to be refunded must be computed on the increase or decrease in tax attributable to the change to the carryback only from the due date (not including extensions) of the return for the redetermination year that generated the carryback and not from the due date of the return for the redetermination year in which the carryback was absorbed. In the case of a change in the amount of a carryover as a result of applying the lookback method, interest is computed from the due date of the return for the year in which the carryover was absorbed. See Examples (8) and (9) of paragraph (h)(9) for an illustration of these rules.
(iii) Changes in the amount of tax liability that generated a subsequent refund. If the amount of tax liability for a redetermination year (as reported on the taxpayer's original return, as subsequently adjusted on examination, as adjusted by amended return, or as redetermined by the last previous application of the look-back method) is decreased by the application of the look-back method, and any portion of the redetermination year tax liability was absorbed by a loss or credit carryback arising in a year subsequent to the redetermination year, the look-back method applies as follows to properly reflect the time period of the use of the tax overpayment. To the extent the amount of tax absorbed because of the carryback exceeds the total hypothetical tax liability for the year (as redetermined under the look-back method) the taxpayer is entitled to receive interest only until the due date (not including extensions) of the return for the year in which the carryback arose.
(A) If the amount refunded because of the NOL is $1,500x: interest is credited to the taxpayer on the entire hypothetical overpayment of $300x from the due date of the 1988 return, when the hypothetical overpayment occurred, until the due date of the 1989 return, when the taxpayer received a refund for the entire amount of the 1988 tax, including the hypothetical overpayment.
(B) If the amount refunded because of the NOL is $1,000x: interest is credited to the taxpayer on the entire amount of the hypothetical overpayment of $300x from the due date of the 1988 return, when the hypothetical overpayment occurred, until the due date of the 1990 return. In this situation interest is credited until the due date of the return for the completion year of the contract, rather than the due date of the return for the year in which the carryback arose, because the amount refunded was less than the redetermined tax liability. Therefore, no portion of the hypothetical overpayment is treated as having been refunded to the taxpayer before the filing year.
(C) If the amount refunded because of the NOL is $1,300x−: interest is credited to the taxpayer on $100x ($1,300x−$1,200x) from the due date of the 1988 return until the due date of the 1989 return because only this portion of the total hypothetical overpayment is treated as having been refunded to the taxpayer before the filing year. However, the taxpayer did not receive a refund for the remaining $200x of the overpayment at that time and, therefore, is credited with interest on $200x through the due date of the tax return for 1990, the filing year. See Examples (10) and (11) of paragraph (h)(9) for a further illustration of this rule.
(d) Simplified marginal impact method -
(1) Introduction. This paragraph (d) provides a simplified method for calculating look-back interest. Any taxpayer may elect this simplified marginal impact method, except that pass-through entities described in paragraph (d)(4) of this section are required to apply the simplified marginal impact method at the entity level with respect to domestic contracts and the owners of those entities do not apply the look-back method to those contracts. Under the simplified marginal impact method, a taxpayer calculates the hypothetical underpayments or overpayments of tax for a prior year based on an assumed marginal tax rate. A taxpayer electing to use the simplified marginal impact method must use the method for each long-term contract for which it reports income (except with respect to domestic contracts if the taxpayer is an owner in a widely held pass-through entity that is required to use the simplified marginal impact method at the entity level for those contracts).
(2) Operation -
(i) In general. Under the simplified marginal impact method, income from those contracts that are completed or adjusted in the filing year is first reallocated in accordance with the procedures of Step One contained in paragraph (c)(2) of this section. Step Two is modified in the following manner. The hypothetical underpayment or overpayment of tax for each year of the contract (a “redetermination year”) is determined by multiplying the applicable regular tax rate (as defined in paragraph (d)(2)(iii)) by the increase or decrease in regular taxable income (or, if it produces a greater amount, by multiplying the applicable alternative minimum tax rate by the increase or decrease in alternative minimum taxable income, for taxpayers subject to the alternative minimum tax without regard to whether tentative minimum tax exceeds regular tax for the redetermination year) that results from reallocating income to the tax year under Step One. Generally, the product of the alternative minimum tax rate and the increase or decrease in alternative minimum taxable income will be the greater of the two amounts described in the preceding sentence only with respect to contracts for which a taxpayer uses the full percentage of completion method only for alternative minimum tax purposes and uses the completed contract method, or the percentage of completion-capitalized cost method, for regular tax purposes. Step Three is then applied. Interest is credited to the taxpayer on the net overpayment and is charged to the taxpayer on the net underpayment for each redetermination year from the due date (determined without regard to extensions) of the return for the redetermination year until the earlier of
(A) The due date (determined without regard to extensions) of the return for the filing year, and
(B) The first date by which both the return is filed and the tax is fully paid.
(ii) Applicable tax rate. For purposes of determining hypothetical underpayments or overpayments of tax under the simplified marginal impact method, the applicable regular tax rate is the highest rate of tax in effect for the redetermination year under section 1 in the case of an individual and under section 11 in the case of a corporation. The applicable alternative minimum tax rate is the rate of tax in effect for the taxpayer under section 55(b)(1). The highest rate is determined without regard to the taxpayer's actual rate bracket and without regard to any additional surtax imposed for the purpose of phasing out multiple tax brackets or exemptions.
(iii) Overpayment ceiling. The net hypothetical overpayment of tax for any redetermination year is limited to the taxpayer's total federal income tax liability for the redetermination year reduced by the cumulative amount of net hypothetical overpayments of tax for that redetermination year resulting from earlier applications of the look-back method. If the reallocation of contract income results in a net overpayment of tax and this amount exceeds the actual tax liability (as of the filing year) for the redetermination year, as adjusted for past applications of the look-back method and taking into account net operating loss, capital loss, or credit carryovers and carrybacks to that year, the actual tax so adjusted is treated as the overpayment for the redetermination year. This overpayment ceiling does not apply when the simplified marginal impact method is applied at the entity level by a widely held pass-through entity in accordance with paragraph (d)(4) of this section.
(iv) Example. The application of the simplified marginal impact method is illustrated by the following example:
(i) In general. After determining a hypothetical underpayment or overpayment of tax for each redetermination year, the taxpayer must determine the interest charged or credited on each of these amounts. Interest on the amount determined under Step Two is determined by applying the overpayment rate designated under section 6621, compounded daily. In general, the time period over which interest is charged on hypothetical underpayments or credited on hypothetical overpayments begins at the due date (not including extensions) of the return for the redetermination year for which the hypothetical underpayment or overpayment determined in Step Two is computed. This time period generally ends on the earlier of:
(A) The due date (not including extensions) of the return for the filing year, and
(B) The date both
(1) The income tax return for the filing year is filed, and
(2) The tax for that year has been paid in full. If a taxpayer uses the simplified marginal impact method contained in paragraph (d), the remainder of this paragraph (c)(4) does not apply.
(ii) Changes in the amount of a loss or credit carryback or carryover. The time period for determining interest may be different in cases involving loss or credit carrybacks or carryovers in order to properly reflect the time period during which the taxpayer (in the case of an underpayment) or the Government (in the case of an overpayment) had the use of the amount determined to be a hypothetical underpayment or overpayment. Thus, if a reallocation of contract income under Step One results in an increase or decrease to a net operating loss carryback (but not a carryforward), the interest due or to be refunded must be computed on the increase or decrease in tax attributable to the change to the carryback only from the due date (not including extensions) of the return for the redetermination year that generated the carryback and not from the due date of the return for the redetermination year in which the carryback was absorbed. In the case of a change in the amount of a carryover as a result of applying the lookback method, interest is computed from the due date of the return for the year in which the carryover was absorbed. See Examples (8) and (9) of paragraph (h)(9) for an illustration of these rules.
(iii) Changes in the amount of tax liability that generated a subsequent refund. If the amount of tax liability for a redetermination year (as reported on the taxpayer's original return, as subsequently adjusted on examination, as adjusted by amended return, or as redetermined by the last previous application of the look-back method) is decreased by the application of the look-back method, and any portion of the redetermination year tax liability was absorbed by a loss or credit carryback arising in a year subsequent to the redetermination year, the look-back method applies as follows to properly reflect the time period of the use of the tax overpayment. To the extent the amount of tax absorbed because of the carryback exceeds the total hypothetical tax liability for the year (as redetermined under the look-back method) the taxpayer is entitled to receive interest only until the due date (not including extensions) of the return for the year in which the carryback arose.
(A) If the amount refunded because of the NOL is $1,500x: interest is credited to the taxpayer on the entire hypothetical overpayment of $300x from the due date of the 1988 return, when the hypothetical overpayment occurred, until the due date of the 1989 return, when the taxpayer received a refund for the entire amount of the 1988 tax, including the hypothetical overpayment.
(B) If the amount refunded because of the NOL is $1,000x: interest is credited to the taxpayer on the entire amount of the hypothetical overpayment of $300x from the due date of the 1988 return, when the hypothetical overpayment occurred, until the due date of the 1990 return. In this situation interest is credited until the due date of the return for the completion year of the contract, rather than the due date of the return for the year in which the carryback arose, because the amount refunded was less than the redetermined tax liability. Therefore, no portion of the hypothetical overpayment is treated as having been refunded to the taxpayer before the filing year.
(C) If the amount refunded because of the NOL is $1,300x−: interest is credited to the taxpayer on $100x ($1,300x−$1,200x) from the due date of the 1988 return until the due date of the 1989 return because only this portion of the total hypothetical overpayment is treated as having been refunded to the taxpayer before the filing year. However, the taxpayer did not receive a refund for the remaining $200x of the overpayment at that time and, therefore, is credited with interest on $200x through the due date of the tax return for 1990, the filing year. See Examples (10) and (11) of paragraph (h)(9) for a further illustration of this rule.
(d) Simplified marginal impact method -
(1) Introduction. This paragraph (d) provides a simplified method for calculating look-back interest. Any taxpayer may elect this simplified marginal impact method, except that pass-through entities described in paragraph (d)(4) of this section are required to apply the simplified marginal impact method at the entity level with respect to domestic contracts and the owners of those entities do not apply the look-back method to those contracts. Under the simplified marginal impact method, a taxpayer calculates the hypothetical underpayments or overpayments of tax for a prior year based on an assumed marginal tax rate. A taxpayer electing to use the simplified marginal impact method must use the method for each long-term contract for which it reports income (except with respect to domestic contracts if the taxpayer is an owner in a widely held pass-through entity that is required to use the simplified marginal impact method at the entity level for those contracts).
(2) Operation -
(i) In general. Under the simplified marginal impact method, income from those contracts that are completed or adjusted in the filing year is first reallocated in accordance with the procedures of Step One contained in paragraph (c)(2) of this section. Step Two is modified in the following manner. The hypothetical underpayment or overpayment of tax for each year of the contract (a “redetermination year”) is determined by multiplying the applicable regular tax rate (as defined in paragraph (d)(2)(iii)) by the increase or decrease in regular taxable income (or, if it produces a greater amount, by multiplying the applicable alternative minimum tax rate by the increase or decrease in alternative minimum taxable income, for taxpayers subject to the alternative minimum tax without regard to whether tentative minimum tax exceeds regular tax for the redetermination year) that results from reallocating income to the tax year under Step One. Generally, the product of the alternative minimum tax rate and the increase or decrease in alternative minimum taxable income will be the greater of the two amounts described in the preceding sentence only with respect to contracts for which a taxpayer uses the full percentage of completion method only for alternative minimum tax purposes and uses the completed contract method, or the percentage of completion-capitalized cost method, for regular tax purposes. Step Three is then applied. Interest is credited to the taxpayer on the net overpayment and is charged to the taxpayer on the net underpayment for each redetermination year from the due date (determined without regard to extensions) of the return for the redetermination year until the earlier of
(A) The due date (determined without regard to extensions) of the return for the filing year, and
(B) The first date by which both the return is filed and the tax is fully paid.
(ii) Applicable tax rate. For purposes of determining hypothetical underpayments or overpayments of tax under the simplified marginal impact method, the applicable regular tax rate is the highest rate of tax in effect for the redetermination year under section 1 in the case of an individual and under section 11 in the case of a corporation. The applicable alternative minimum tax rate is the rate of tax in effect for the taxpayer under section 55(b)(1). The highest rate is determined without regard to the taxpayer's actual rate bracket and without regard to any additional surtax imposed for the purpose of phasing out multiple tax brackets or exemptions.
(iii) Overpayment ceiling. The net hypothetical overpayment of tax for any redetermination year is limited to the taxpayer's total federal income tax liability for the redetermination year reduced by the cumulative amount of net hypothetical overpayments of tax for that redetermination year resulting from earlier applications of the look-back method. If the reallocation of contract income results in a net overpayment of tax and this amount exceeds the actual tax liability (as of the filing year) for the redetermination year, as adjusted for past applications of the look-back method and taking into account net operating loss, capital loss, or credit carryovers and carrybacks to that year, the actual tax so adjusted is treated as the overpayment for the redetermination year. This overpayment ceiling does not apply when the simplified marginal impact method is applied at the entity level by a widely held pass-through entity in accordance with paragraph (d)(4) of this section.
(iv) Example. The application of the simplified marginal impact method is illustrated by the following example:

Source

26 CFR § 1.460-6


Scoping language

None
Is this correct? or