1. Short title This Act may be cited as the Strengthening Social Security Act of 2018 . 2. Determination of taxable wages and self-employment income above contribution and benefit base after 2018 (a) Determination of taxable wages above contribution and benefit base after 2018 (1) Amendments to the Internal Revenue Code of 1986 Section 3121 of the Internal Revenue Code of 1986 is amended— (A) in subsection (a)(1), by inserting the applicable percentage (determined under subsection (c)(1)) of before that part of the remuneration ; and (B) in subsection (c), by striking (c) Included and excluded service.— For purposes of this chapter, if and inserting the following: (c) Special rules for wages and employment (1) Applicable percentage of remuneration in determining taxable wages For purposes of subsection (a)(1), the applicable percentage for a calendar year shall be equal to— (A) for 2019, 80 percent, (B) for 2020 through 2022, the applicable percentage under this paragraph for the previous year, decreased by 20 percentage points, and (C) for 2023 and each year thereafter, 0 percent. (2) Included and excluded service For purposes of this chapter, if . (2) Amendments to the Social Security Act Section 209 of the Social Security Act ( 42 U.S.C. 409 ) is amended— (A) in subsection (a)(1)(I)— (i) by inserting and before 2019 after 1974 ; and (ii) by inserting and after the semicolon; (B) in subsection (a)(1), by adding at the end the following new subparagraph: (J) The applicable percentage (determined under subsection (l)) of that part of remuneration which, after remuneration (other than remuneration referred to in the succeeding subsections of this section) equal to the contribution and benefit base (determined under section 230) with respect to employment has been paid to an individual during any calendar year after 2018 with respect to which such contribution and benefit base is effective, is paid to such individual during such calendar year;