SSI: deemed benefit is capped at the individual rate instead of the no-deeming amount, and couples are identified by tax roles #10138

Two SSI gaps, found while registering a population analysis in PolicyEngine/microcosm-dynamics and reproduced on main at bee8954716 (2.39.1) with invented households (2026: individual rate $994, couple rate $1,491, resource limits $2,000 and $3,000).

1. Spousal deeming caps the benefit at the individual rate, not at the benefit without deeming

ssi_if_takes_up caps SSI at the individual Federal benefit rate whenever spousal income deeming applies. 20 CFR 416.1163(e)(2) says:

Your SSI benefit under the deeming rules cannot be higher than it would be if deeming did not apply. Therefore, your benefit is the lesser of the amount computed under the rules in paragraph (d)(2) of this section or the amount remaining after we subtract only your own countable income from an individual's Federal benefit rate.

The cap is the claimant's no-deeming benefit, which is below the individual rate whenever the claimant has countable income of their own.

Florida couple: claimant aged 70 with Social Security of $743 a month and $1,500 in the bank; spouse aged 64 with Social Security of $100 and wages of $400 a month.

On main, the cut lowers the couple's income and also lowers annual SSI, from $6,006 to $5,220. Under the regulation SSI rises from $3,252 to $5,220.

Related: 416.1163(f)(5) deems no spousal income while the $30 medical facility rate applies, but main subtracts deemed income from the $30.

2. SSI couples are identified by tax-unit roles

ssi_claim_is_joint requires both spouses to be the head or spouse of their tax unit. When roles are not supplied, PE-US gives those roles to the two oldest adults of the tax unit. The ineligible spouse used for income deeming (is_ssi_ineligible_spouse) has the same dependency. Under 20 CFR 416.1801(c), an eligible spouse is someone eligible for SSI who is the spouse of another person eligible for SSI and lives in the same household. Under 416.1160(d), an ineligible spouse is "someone who lives with you as your husband or wife and is not eligible for SSI benefits". Neither definition refers to tax roles.

• An aged couple aged 70 and 68 (Social Security $700 and $600), sharing a tax unit with a 90-year-old: the wife is a tax dependent, so main computes two individuals at $314 and $414 a month. Under 416.1802(b) and 416.412 they are a couple: $1,491 − $1,280 = $211, or $105.50 each.
• The same structure with a non-aged husband who is a tax dependent: the husband's $2,000 a month of wages is not deemed to the claimant, so main pays $414 a month. Under 416.1163 the claimant's countable income exceeds the couple rate, so the payment is $0.
• A citizen aged 70 married to an undocumented aged 68-year-old is a joint claim on main, because the joint test reads only aged/blind/disabled status. Under 416.1801(c) the spouse is not eligible for SSI, so their income should be deemed.

Resource deeming (416.1202, 416.1205) was missing in the 2.18.0 release where this was first seen. #10040 added it, so that part already holds on main: an ineligible spouse's $3,500 now fails the $3,000 couple limit. #10040 listed the joint-claim and income-deeming role dependency as a known limitation.

Pinned regulation copies (Cornell LII, with SHA-256 values) and the reviewer scripts are in the microcosm-dynamics evidence folder for the depletion-cut registration (pe-us-depletion-cut-population-20261001/sources/).