(2) Application of contribution bases (A) Compensation in excess of applicable base excluded (i) In general The term “compensation” does not include that part of remuneration paid during any calendar year to an individual by an employer after remuneration equal to the applicable base has been paid during such calendar year to such individual by such employer for services rendered as an employee to such employer. (ii) Remuneration not treated as compensation excluded There shall not be taken into account under clause (i) remuneration which (without regard to clause (i)) is not treated as compensation under this subsection. (iii) Hospital insurance taxes Clause (i) shall not apply to— (I) so much of the rate applicable under section 3201(a) or 3221(a) as does not exceed the rate of tax in effect under section 3101(b), and (II) so much of the rate applicable under section 3211(a) as does not exceed the rate of tax in effect under section 1401(b). (B) Applicable base (i) Tier 1 taxes Except as provided in clause (ii), the term “applicable base” means for any calendar year the contribution and benefit base determined under section 230 of the Social Security Act for such calendar year. (ii) Tier 2 taxes, etc. For purposes of— (I) the taxes imposed by sections 3201(b), 3211(b), and 3221(b), and (II) computing average monthly compensation under section 3(j) of the Railroad Retirement Act of 1974 (except with respect to annuity amounts determined under subsection (a) or (f)(3) of section 3 of such Act), clause (2) of the first sentence, and the second sentence, of subsection (c) of section 230 of the Social Security Act shall be disregarded. (C) Successor employers For purposes of this paragraph, the second sentence of section 3121(a)(1) (relating to successor employers) shall apply, except that— (i) the term “services” shall be substituted for “employment” each place it appears, (ii) the term “compensation” shall be substituted for “remuneration (other than remuneration referred to in the succeeding paragraphs of this subsection)” each place it appears, and (iii) the terms “employer”, “services”, and “compensation” shall have the meanings given such terms by this section.