26 U.S.C. § 22 — Credit for the elderly and the permanently and totally disabled

(a) A "qualified individual" can claim a tax credit equal to 15 percent of their "section 22 amount" for the year. (b) A qualified individual is someone who either turned 65 before the tax year ended, or who retired on disability before the tax year ended and was permanently and totally disabled at retirement. (c) The "section 22 amount" works like this: start with an "initial amount," then reduce it under the rules below. The initial amount is normally $5,000 for a single person, or a joint return where only one spouse is a qualified individual; $7,500 for a joint return where both spouses are qualified individuals; or $3,750 for a married person filing a separate return. But if the qualified individual has not attained age 65, the initial amount cannot exceed their "disability income" for the year — income includable in gross income under section 72 or 105(a) that represents wages, or payments in lieu of wages, for the period the individual is absent from work because of permanent and total disability. On a joint return where both spouses are qualified individuals and at least one has not attained age 65: if neither has attained age 65, the initial amount cannot exceed the sum of both spouses' disability income; if one spouse has attained age 65, it cannot exceed $5,000 plus the disability income of the spouse who has not attained age 65. Next, the initial amount is reduced by the total of any pension, annuity, or disability benefits the individual, or either spouse on a joint return, received that are excluded from gross income and payable under title II of the Social Security Act, the Railroad Retirement Act of 1974, or a law administered by the Department of Veterans Affairs, or that are excluded from gross income under any other provision of law not in this title — except no reduction is made for certain amounts described in section 104(a)(4). An amount treated as a social security benefit under section 86(d)(3), covering certain workmen's compensation benefits, is treated as a title II disability benefit for this reduction too. (d) If the taxpayer's adjusted gross income exceeds $7,500 for a single individual, $10,000 for a joint return, or $5,000 for a married individual filing separately, the section 22 amount is reduced by one-half of the excess over that limit. (e) Except for a husband and wife who live apart at all times during the taxable year, a married taxpayer must file a joint return with their spouse to claim this credit; marital status is determined under section 7703. An individual is "permanently and totally disabled" if unable to engage in any substantial gainful activity because of a medically determinable physical or mental impairment that can be expected to result in death, or that has lasted or can be expected to last for a continuous period of not less than 12 months — and the individual must furnish proof of this in the form, manner, and at the times the Secretary requires. (f) No credit is allowed under this section to any nonresident alien.