in the group market. (C) A Medicare Advantage plan under part C of title XVIII of the Social Security Act. (D) A prescription drug plan offered under part D of such title XVIII. (4) Reduction in premiums treated as rebates For purposes of this subsection, a reduction in premiums owed by an individual for a month shall be treated as a premium rebate paid to such individual on the first day of such month. (l) Medicaid managed care plans reduction for 2018 In the case of a medicaid managed care organization (as defined in section 1903(m)(1)(A) of the Social Security Act), the fee described in subsection (a)(1) shall be reduced by an amount equal to 2 percent of the net premiums written for coverage under a medicaid managed care plan (under section 1903(m) or section 1932 of such Act) for calendar year 2018. . (b) Medical loss ratio Section 2718 of the Public Health Service Act is amended by adding at the end the following new subsection: (f) Amounts expended for premium rebates not included No amount expended pursuant to subsections (k) or (l) of section 9010 of the Patient Protection and Affordable Care Act shall be taken into account for purposes of this section. . (c) Conforming amendment Section 9010(b)(1) of the Patient Protection and Affordable Care Act is amended by striking the fee under this section and inserting the amount determined under this subsection . (d) Effective date (1) In general Except as otherwise provided in this subsection, the amendments made by this section shall apply with respect to calendar years beginning after December 31, 2017. (2) Medical loss ratio The amendment made by subsection (b) shall apply with respect to plan years beginning after December 31, 2017.