social security taxes
(2) Social security taxes For purposes of paragraph (1)— (A) In general The term “social security taxes” means, with respect to any taxpayer for any taxable year— (i) the amount of the taxes imposed by sections 3101 and 3201(a) on amounts received by the taxpayer during the calendar year in which the taxable year begins, (ii) 50 percent of the taxes imposed by section 1401 on the self-employment income of the taxpayer for the taxable year, and (iii) 50 percent of the taxes imposed by section 3211(a) on amounts received by the taxpayer during the calendar year in which the taxable year begins. (B) Coordination with special refund of social security taxes The term “social security taxes” shall not include any taxes to the extent the taxpayer is entitled to a special refund of such taxes under section 6413(c). (C) Special rule Any amounts paid pursuant to an agreement under section 3121(l) (relating to agreements entered into by American employers with respect to foreign affiliates) which are equivalent to the taxes referred to in subparagraph (A)(i) shall be treated as taxes referred to in such subparagraph.
26 USC § 24(d)(2)
None identified, default scope is assumed to be the parent (subpart A) of this section.