subparagraph (D). (b) Effective date The amendment made by this section shall apply to months beginning after December 31, 2018. B Alternative Minimum Tax 12001. Repeal of tax for corporations (a) In general Section 55(a) is amended by striking There and inserting In the case of a taxpayer other than a corporation, there . (b) Conforming amendments (1) Section 38(c)(6) is amended by adding at the end the following new subparagraph: (E) Corporations In the case of a corporation, this subsection shall be applied by treating the corporation as having a tentative minimum tax of zero. . (2) (A) Section 55(b)(1) is amended to read as follows: (1) Amount of tentative tax (A) In general The tentative minimum tax for the taxable year is the sum of— (i) 26 percent of so much of the taxable excess as does not exceed $175,000, plus (ii) 28 percent of so much of the taxable excess as exceeds $175,000. The amount determined under the preceding sentence shall be reduced by the alternative minimum tax foreign tax credit for the taxable year. (B) Taxable excess For purposes of this subsection, the term taxable excess means so much of the alternative minimum taxable income for the taxable year as exceeds the exemption amount. (C) Married individual filing separate return In the case of a married individual filing a separate return, subparagraph (A) shall be applied by substituting 50 percent of the dollar amount otherwise applicable under clause (i) and cause (ii) thereof. For purposes of the preceding sentence, marital status shall be determined under section 7703. . (B) Section 59(a) is amended— (i) by striking subparagraph (A)(i) or (B)(i) of section 55(b)(1) (whichever applies) in lieu of the highest rate of tax specified in section 1 or 11 (whichever applies) in paragraph (1)(C) and inserting section 55(b)(1) in lieu of the highest rate of tax specified in section 1 , and (ii) in paragraph (2), by striking means and all that follows and inserting means the amount determined under the first sentence of section 55(b)(1). . (C)