on by a partnership which is not excluded under section 1402 of such Code, and (2) for whom gross self-employment income during the first taxable year beginning in 2020 is less than 90 percent of such individual’s gross self-employment income during the first taxable year beginning in 2019. (d) Qualified self-employment income For purposes of this section— (1) In general The term qualified self-employment income means the product of— (A) the specified gross self-employment income reduction for the first taxable year beginning in 2020, multiplied by (B) the ratio of— (i) self-employment income (as determined under section 1402(b) of such Code, but not below zero) for the first taxable year beginning in 2019, divided by (ii) gross self-employment income for the first taxable year beginning in 2019. (2) Limitation based on modified adjusted gross income In the case of any taxpayer, qualified self-employment income shall not exceed the excess (if any) of— (A) modified adjusted gross income for the first taxable year beginning in 2019, over (B) modified adjusted gross income for the first taxable year beginning in 2020. (3) Specified gross self-employment income reduction For purposes of paragraph (1), the term specified gross self-employment income reduction means, with respect to a taxable year, the excess (if any) of— (A) 90 percent of gross self-employment income for the taxable year preceding such taxable year, over (B) gross self-employment income for such taxable year. (e) Gross self-employment income For purposes of this section, the term gross self-employment income means, with respect to any taxable year, the sum of— (1) the eligible self-employed individuals’ gross income derived from all trades or business carried on by such individual for purposes of determining net earnings from self-employment under section 1402 of such Code for such taxable year, and (2) the eligible individual’s distributive share of gross income (as determined under section 702(c) of such Code) from any trade or business carried on