production of qualifying production property substantially all of the research and development of which occurred in the United States, subsection (a) shall be applied by substituting 15 percent for 9 percent . (B) Special rule when taxable income used to determine deduction In the case of any taxable year for which the taxpayer’s qualified production activities income exceeds the taxpayer’s taxable income (determined without regard to this section), the amount of taxable income to which the 15 percent amount in subparagraph (A) applies under subsection (a)(1) shall be an amount equal to the amount which bears the same ratio to such taxable income (as so determined) as— (i) the amount of qualified production activities income of the taxpayer for the taxable year which is attributable to the manufacture or production of qualifying production property substantially all of the research and development with respect to which occurred in the United States, bears to (ii) all qualified production activities income of the taxpayer for the taxable year. (C) Termination This paragraph shall not apply to taxable years beginning after December 31, 2024. . (b) Effective date The amendments made by this section shall apply to taxable years beginning after the date of the enactment of this Act.