unused credit year
(1) In general If the amount of the foreign oil and gas taxes paid or accrued during any taxable year exceeds the limitation provided by subsection (a) for such taxable year (hereinafter in this subsection referred to as the “unused credit year”), such excess shall be deemed to be foreign oil and gas taxes paid or accrued in the first preceding taxable year and in any of the first 10 succeeding taxable years, in that order and to the extent not deemed tax paid or accrued in a prior taxable year by reason of the limitation imposed by paragraph (2). Such amount deemed paid or accrued in any taxable year may be availed of only as a tax credit and not as a deduction and only if the taxpayer for such year chooses to have the benefits of this subpart as to taxes paid or accrued for that year to foreign countries or possessions.