. (B) Dividends from 20-percent owned corporations Section 243(c)(1) is amended— (i) by striking 80 percent and inserting 65 percent , and (ii) by striking 70 percent and inserting 50 percent . (C) Conforming amendment The heading for section 243(c) is amended by striking Retention of 80-percent dividend received deduction and inserting Increased percentage . (2) Dividends received from FSC Section 245(c)(1)(B) is amended— (A) by striking 70 percent and inserting 50 percent , and (B) by striking 80 percent and inserting 65 percent . (3) Limitation on aggregate amount of deductions Section 246(b)(3) is amended— (A) by striking 80 percent in subparagraph (A) and inserting 65 percent , and (B) by striking 70 percent in subparagraph (B) and inserting 50 percent . (4) Reduction in deduction where portfolio stock is debt-financed Section 246A(a)(1) is amended— (A) by striking 70 percent and inserting 50 percent , and (B) by striking 80 percent and inserting 65 percent . (5) Income from sources within the United States Section 861(a)(2) is amended— (A) by striking 100/70th and inserting 100/50th in subparagraph (B), and (B) in the flush sentence at the end— (i) by striking 100/80th and inserting 100/65th , and (ii) by striking 100/70th and inserting 100/50th . (d) 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) Certain conforming amendments The amendments made by paragraphs (2), (3), and (4) of subsection (b) shall apply to distributions after December 31, 2017. (e) Normalization requirements (1) In general A normalization method of accounting shall not be treated as being used with respect to any public utility property for purposes of section 167 or 168 of the Internal Revenue Code of 1986 if the taxpayer, in computing its cost of service for ratemaking purposes and reflecting operating results in its regulated books of account, reduces the excess tax reserve more rapidly or to a