26 CFR § 1.37-1 - General rules for the credit for the elderly.
(a) In general. In the case of an individual, section 37 provides a credit against the tax imposed by chapter 1 of the Internal Revenue Code of 1954. This section and §§ 1.37-2 and 1.37-3 provide guidance in the computation of the credit for the elderly provided under section 37 for taxable years beginning after 1975. For rules relating to the computation of the retirement income credit provided under section 37 for taxable years beginning before 1976, see 26 CFR 1.37-1 through 1.37-5 (Rev. as of April 1, 1980). Note that section 403 of the Tax Reduction and Simplification Act of 1977 provides that a taxpayer may elect to compute the credit under section 37 for the taxpayer's first taxable year beginning in 1976 in accordance with the rules applicable to taxable years beginning before 1976.
(b) Limitation on the amount of the credit. The credit allowed by section 37 for a taxable year shall not exceed the tax imposed by chapter 1 of the Code for the taxable year (reduced, in the case of a taxable year beginning before 1979, by the general tax credit allowed by section 42).
(c) Married couples must file joint returns. If the taxpayer is married at the close of the taxable year, the credit provided by section 37 shall be allowed only if the taxpayer and the taxpayer's spouse file a joint return for the taxable year. The preceding sentence shall not apply in the case of a husband and wife who are not members of the same household at any time during the taxable year. For the determination of marital status, see §§ 143 and 1.143-1.
(d) Nonresident aliens ineligible. No credit is allowed under section 37 to any individual for any taxable year during which that individual is at any time a nonresident alien unless the individual is treated, by reason of an election under section 6013 (g) or (h), as a resident of the United States for that taxable year.