tax (as defined in section 55(c)) and inserting the regular tax liability (as defined in section 26(b)) . (d) Effective dates (1) In general Except as otherwise provided in this subsection, the amendments made by this section shall apply to taxable years beginning after December 31, 2017. (2) Prior elections with respect to certain tax preferences So much of the amendment made by subsection (a) as relates to the repeal of section 59(e) of the Internal Revenue Code of 1986 shall apply to amounts paid or incurred after December 31, 2017. (3) Treatment of net operating loss carrybacks For purposes of section 56(d) of the Internal Revenue Code of 1986 (as in effect before its repeal), the amount of any net operating loss which may be carried back from a taxable year beginning after December 31, 2017, to taxable years beginning before January 1, 2018, shall be determined without regard to any adjustments under section 56(d)(2)(A) of such Code (as so in effect). III Business tax reform A Tax rates 3001. Reduction in corporate tax rate (a) In general Section 11(b) is amended to read as follows: (b) Amount of tax (1) In general Except as otherwise provided in this subsection, the amount of the tax imposed by subsection (a) shall be 20 percent of taxable income. (2) Special rule for personal service corporations (A) In general In the case of a personal service corporation (as defined in section 448(d)(2)), the amount of the tax imposed by subsection (a) shall be 25 percent of taxable income. (B) References to corporate rate Any reference to the rate imposed under this section or to the highest rate in effect under this section (or any similar reference) shall be determined without regard to the rate imposed with respect to personal service corporations (as so defined). . (b) Conforming amendments (1) (A) Part I of subchapter P of chapter 1 is amended by striking section 1201 (and by striking the item relating to such section in the table of sections for such part). (B) Section 12 is amended by striking paragraph (4). (C)