paragraph (11) and by inserting after paragraph (9) the following new paragraph: (10) Special rule for taxable years beginning in 2019 and 2020 (A) In general In the case of any taxable year beginning in 2019 or 2020, paragraph (1)(B) shall be applied by substituting 50 percent for 30 percent . (B) Election to use 2019 income for taxable years beginning in 2020 (i) In general Subject to clause (ii), in the case of any taxable year beginning in 2020, the taxpayer may elect to apply this subsection by substituting the adjusted taxable income of the taxpayer for the last taxable year beginning in 2019 for the adjusted taxable income for such taxable year. (ii) Special rule for short taxable years No election may be made under clause (i) with respect to any taxable year beginning in 2020 if such taxable year is a short taxable year. . (b) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2018. 2207. Technical amendments regarding qualified improvement property (a) In general Section 168 of the Internal Revenue Code of 1986 is amended— (1) in subsection (e)— (A) in paragraph (3)(E), by striking and at the end of clause (v), by striking the period at the end of clause (vi) and inserting , and , and by adding at the end the following new clause: (vii) any qualified improvement property. , and (B) in paragraph (6)(A), by inserting made by the taxpayer after any improvement , and (2) in the table contained in subsection (g)(3)(B)— (A) by striking the item relating to subparagraph (D)(v), and (B) by inserting after the item relating to subparagraph (E)(vi) the following new item: (E)(vii) 20 . (b) Effective date The amendments made by this section shall take effect as if included in section 13204 of Public Law 115–97 . 2208. Installments not to prevent credit or refund of overpayments or increase estimated taxes (a) In general Section 965(h) of the Internal Revenue Code of 1986 is amended by adding at the end the following new paragraph: (7) Installments not to