26 CFR 1.1314(a)-1 - Ascertainment of amount of adjustment in year of error.
(a) In computing the amount of the adjustment under sections 1311 to 1315, inclusive, there must first be ascertained the amount of the tax previously determined for the taxpayer as to whom the error was made for the taxable year with respect to which the error was made. The tax previously determined for any taxable year may be the amount of tax shown on the taxpayer's return, but if any changes in that amount have been made, they must be taken into account. In such cases, the tax previously determined will be the sum of the amount shown as the tax by the taxpayer upon his return and the amounts previously assessed (or collected without assessment) as deficiencies, reduced by the amount of any rebates made. The amount shown as the tax by the taxpayer upon his return and the amount of any rebates or deficiencies shall be determined in accordance with the provisions of section 6211 and the regulations thereunder.
(1) The tax previously determined may consist of tax for any taxable year beginning after December 31, 1931, imposed by subtitle A of the Internal Revenue Code of 1954, by chapter 1 and subchapters A, B, D, and E of chapter 2 of the Internal Revenue Code of 1939, or by the corresponding provisions of prior internal revenue laws, or by any one or more of such provisions.
(2) After the tax previously determined has been ascertained, a recomputation must then be made under the laws applicable to said taxable year to ascertain the increase or decrease in tax, if any, resulting from the correction of the error. The difference between the tax previously determined and the tax as recomputed after correction of the error will be the amount of the adjustment.
(c) No change shall be made in the treatment given any item upon which the tax previously determined was based other than in the correction of the item or items with respect to which the error was made. However, due regard shall be given to the effect that such correction may have on the computation of gross income, taxable income, and other matters under chapter 1 of the Code. If the treatment of any item upon which the tax previously determined was based, or if the application of any provisions of the internal revenue laws with respect to such tax, depends upon the amount of income (e.g. charitable contributions, foreign tax credit, dividends received credit, medical expenses, and percentage depletion), readjustment in these particulars will be necessary as part of the recomputation in conformity with the change in the amount of the income which results from the correct treatment of the item or items in respect of which the error was made.
(e) The application of this section may be illustrated by the following example:
(2) The amount of the adjustment is computed as follows:
|Tax previously determined for 1949||$7,788|
|Net income for 1949 upon which tax previously determined was based||30,000|
|Less: Rents erroneously included||5,000|
|Adjustment for contributions (add 15 percent of $5,000)||750|
|Net income as adjusted||25,750|
|Tax as recomputed||6,152|
|Tax previously determined||7,788|
|Amount of adjustment to be refunded or credited||1,636|