(i) by striking 15 percent in subparagraph (C) and inserting 13 percent , (ii) by striking 20 percent in subparagraph (D) and inserting 18 percent , (iii) by striking 25 percent in subparagraph (E) and inserting 23 percent , and (iv) by striking 28 percent in subparagraph (F) and inserting 26 percent . (B) Rate under alternative minimum tax Paragraph (3) of section 55(b) of such Code is amended— (i) by striking 15 percent in subparagraph (C) and inserting 13 percent , (ii) by striking 20 percent in subparagraph (D) and inserting 18 percent , and (iii) by striking 25 percent in subparagraph (E) and inserting 23 percent . (C) Conforming amendments The following sections are each amended by striking 20 percent and inserting 18 percent : (i) Section 1445(e)(1). (ii) The second sentence of section 7518(g)(6)(A). (iii) Section 53511(f)(2) of title 46, United States Code. (b) Corporate tax rates (1) In general Section 11(b) of the Internal Revenue Code of 1986 is amended— (A) in paragraph (1)— (i) by striking 15 percent in subparagraph (A) inserting 13 percent , (ii) by striking 25 percent in subparagraph (B) and inserting 23 percent , (iii) by striking 34 percent in subparagraph (C) and inserting 32 percent , and (iv) by striking 35 percent in subparagraph (C) and inserting 33 percent , and (B) in paragraph (2), by striking 35 percent and inserting 33 percent . (2) Conforming amendments (A) Section 1201(a) of such Code is amended by striking 35 percent each place it appears and inserting 33 percent . (B) Paragraphs (1) and (2) of section 1445(e) of such Code are each amended by striking 35 percent and inserting 33 percent . (c) Effective date (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) Amendments related to withholding The amendments made by subsections (a)(1)(D)(iii) and (c)(2)(B) shall take effect on January 1, 2018.