; tax on combustible fossil fuels Part I—Reduction of certain social security taxes Part II—Tax on combustible fossil fuels Part III—Tax on certain additional imported products Part IV—Tax on fluorinated greenhouse gases Part V—Supermajority required To change revenue neutrality I Reduction of certain social security taxes Sec. 4691. Social Security taxes and benefits. 4691. Social Security taxes and benefits (a) Amounts appropriated to social security trust funds (1) In general There are hereby appropriated to the social security trust funds an amount equal to the excess (if any) of— (A) net revenues received in the Treasury from the taxes imposed by parts II, III, and IV, over (B) the net expenditures from the Treasury under sections 2 and 3 of the Raise Wages, Cut Carbon Act of 2019 . (2) Allocation among funds Amounts appropriated under paragraph (1) shall be allocated among such funds as determined appropriate by the Managing Trustee of the Board of Trustees of the Trust Funds (within the meaning of title II of the Social Security Act), in cooperation with the Railroad Retirement Board. (b) Reduction in certain social security taxes (1) In general The rate of each specified social security tax for each calendar year (determined without regard to this section) shall be reduced by the number of percentage points equal to— (A) such rate, multiplied by (B) the reduction percentage determined by the Secretary for such calendar year. (2) Reduction percentage The reduction percentage determined by the Secretary under paragraph (1) for any calendar year shall be the percentage which the Secretary estimates will result in aggregate appropriations into each trust fund equal to the amount which would (without regard to this section) be appropriated to each trust fund for such calendar year. (c) Definitions For purposes of this subchapter— (1) Specified social security tax The term specified social security tax means— (A) the tax imposed by section 3101(a) (and so much of the tax imposed by section 3201(a) or section