(c) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2017. (d) Phased inclusion of remaining balance of policyholders surplus accounts In the case of any stock life insurance company which has a balance (determined as of the close of such company’s last taxable year beginning before January 1, 2018) in an existing policyholders surplus account (as defined in section 815 of the Internal Revenue Code of 1986, as in effect before its repeal), the tax imposed by section 801 of such Code for the first 8 taxable years beginning after December 31, 2017, shall be the amount which would be imposed by such section for such year on the sum of— (1) life insurance company taxable income for such year (within the meaning of such section 801 but not less than zero), plus (2) 1/8 of such balance. 13515. Modification of proration rules for property and casualty insurance companies (a) In general Section 832(b)(5)(B) is amended— (1) by striking 15 percent and inserting the applicable percentage , and (2) by inserting at the end the following new sentence: For purposes of this subparagraph, the applicable percentage is 5.25 percent divided by the highest rate in effect under section 11(b). . (b) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2017. 13516. Repeal of special estimated tax payments (a) In general Part III of subchapter L of chapter 1 is amended by striking section 847 (and by striking the item relating to such section in the table of sections for such part). (b) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2017. 13517. Capitalization of certain policy acquisition expenses (a) Amortization period Section 848 is amended by striking 120-month each place it appears in subsections (a)(2) and (b)(1) and inserting 600-month . (b) Determination of expenses Paragraph (1) of section 848(c) is amended— (1) by striking 1.75 percent in subparagraph