subparagraph (A), source of income includes the following: (i) A housing voucher under section 8 of the United States Housing Act of 1937 ( 42 U.S.C. 1437f ) and any form of Federal, State, or local housing assistance provided to a family or provided to a housing owner on behalf of a family, including rental vouchers, rental assistance, and rental subsidies from nongovernmental organizations. (ii) Any income received during a taxable year as Social Security benefits, as defined in section 86(d) of the Internal Revenue Code of 1986, or as supplemental security income benefits under title XVI of the Social Security Act ( 42 U.S.C. 1381 et seq. ). (iii) Any income received by court order, including spousal support and child support. (iv) Any payment from a trust, guardian, or conservator. (v) Any other lawful source of income. (d) Aggregation rules All persons treated as a single employer under subsection (a) or (b) of section 52, or subsection (m) or (o) of section 414, shall be treated as one person for purposes of applying subsection (b). . (b) Effective date The amendment made by this section shall apply to sales and exchanges after December 31, 2023.