For purposes of this section— (1) Applicable annual addition (A) In general The term applicable annual addition means any of the following made to or on behalf of an individual: (i) An annual addition (within the meaning of section 415(c)(2)). (ii) Any contribution to an individual retirement plan, including any employer or employee contribution to a simplified employee pension under section 408(k) or a simple retirement account under section 408(p). (iii) Any deferral under an eligible deferred compensation plan described in section 457(b) which is maintained by an eligible employer described in section 457(e)(1)(A). (B) Rollover contributions disregarded A rollover contribution under section 402(c), 403(b)(8), 408(d)(3)(A)(ii), or 457(e)(16) shall not be treated as an annual addition. (2) Applicable dollar amount (A) In general The term applicable dollar amount means $4,000,000. (B) Adjustment for inflation In the case of any taxable year beginning after 2019, the $4,000,000 amount under subparagraph (A) shall be increased by an amount equal to the product of— (i) such amount, and (ii) the cost-of-living adjustment under section 1(f)(3) for the calendar year in which such taxable year begins, determined by substituting calendar year 2019 for calendar year 2016 in subparagraph (A)(ii) thereof. (C) Rounding If any amount as adjusted under subparagraph (B) is not a multiple of $1,000, such amount shall be rounded to the next lowest multiple of $1,000. (3) Applicable retirement plan The term applicable retirement plan means— (A) a defined contribution plan to which section 401(a) or 403(a) applies, (B) an annuity contract under section 403(b), (C) an eligible deferred compensation plan described in section 457(b) which is maintained by an eligible employer described in section 457(e)(1)(A), or (D) an individual retirement plan. (d) Regulations The Secretary shall prescribe such regulations and guidance as are necessary or appropriate to carry out the purposes of this section, including regulations or guidance that