26 CFR §1.1312-3 — -3 Double exclusion of an item of gross income.

1. (a)Items included in income or with respect to which a tax was paid.
   1. (1)Paragraph (3)(A) of section 1312 applies if the determination requires the exclusion, from a taxpayer's gross income, of an item included in a return filed by the taxpayer, or with respect to which tax was paid, and which was erroneously excluded or omitted from the gross income of the same taxpayer for another taxable year or of a related taxpayer for the same or another taxable year.
   2. (2)The application of subparagraph (1) of this paragraph may be illustrated by the following examples:
2. (b)Items not included in income and with respect to which the tax was not paid.
   1. (1)Paragraph (3)(B) of section 1312 applies if the determination requires the exclusion from gross income of an item not included in a return filed by the taxpayer and with respect to which a tax was not paid, but which is includible in the gross income of the same taxpayer for another taxable year, or in the gross income of a related taxpayer for the same or another taxable year. This is one of the two circumstances in which the maintenance of an inconsistent position is not a requirement for an adjustment, but the requirements in paragraph (a) of § 1.1311(b)-2 must be fulfilled (correction not barred at time of erroneous action).
   2. (2)The application of subparagraph (1) of this paragraph may be illustrated by the following examples: