(a) Taxable year ending before January 1, 1971.

(1) For taxable years ending before January 1, 1971, in the case of a joint return of husband and wife, or the return of a surviving spouse as defined in section 2(b), the tax imposed by section 1 shall be twice the tax that would be imposed if the taxable income were reduced by one-half. For rules relating to the filing of joint returns of husband and wife, see section 6013 and the regulations thereunder.

(2) The method of computing, under section 2(a), the tax of husband and wife in the case of a joint return, or the tax of a surviving spouse, is as follows:

(i) First, the taxable income is reduced by one-half. Second, the tax is determined as provided by section 1 by using the taxable income so reduced. Third, the tax so determined, which is the tax that would be determined if the taxable income were reduced by one-half, is then multiplied by two to produce the tax imposed in the case of the joint return or the return of a surviving spouse, subject, however, to the allowance of any credits against the tax under the provisions of sections 31 through 38 and the regulations thereunder.

(ii) The limitation under section 1(c) of the tax to an amount not in excess of a specified percent of the taxable income for the taxable year is to be applied before the third step above, that is, the limitation to be applied upon the tax is determined as the applicable specified percent of one-half of the taxable income for the taxable year (such one-half of the taxable income being the actual aggregate taxable income of the spouses, or the total taxable income of the surviving spouse, as the case may be, reduced by one-half). For the percent applicable in determining the limitation of the tax under section 1(c), see §1.1-2(a). After such limitation is applied, then the tax so limited is multiplied by two as provided in section 2(a) (the third step above).

(iii) The following computation illustrates the method of application of section 2(a) in the determination of the tax of a husband and wife filing a joint return for the calendar year 1965. If the combined gross income is $8,200, and the only deductions are the two exemptions of the taxpayers under section 151(b) and the standard deduction under section 141, the tax on the joint return for 1965, without regard to any credits against the tax, is $1,034.20 determined as follows:

(b) Taxable years beginning after December 31, 1970.

(1) For taxable years beginning after December 31, 1970, in the case of a joint return of husband and wife, or the return of a surviving spouse as defined in section 2(a) of the Code as amended by the Tax Reform Act of 1969, the tax shall be determined in accordance with the table contained in section 1(a) of the Code as so amended. For rules relating to the filing of joint returns of husband and wife see section 6013 as amended and the regulations thereunder.

(2) The following computation illustrates the method of computing the tax of a husband and wife filing a joint return for calendar year 1971. If the combined gross income is $8,200, and the only deductions are the two exemptions of the taxpayers under section 151(b), as amended, and the standard deduction under section 141, as amended, the tax on the joint return for 1971, without regard to any credits against the tax, is $968.46, determined as follows:

(3) The limitation under section 1348 with respect to the maximum rate of tax on earned income shall apply to a married individual only if such individual and his spouse file a joint return for the taxable year.

(c) Death of a spouse. If a joint return of a husband and wife is filed under the provisions of section 6013 and if the husband and wife have different taxable years solely because of the death of either spouse, the taxable year of the deceased spouse covered by the joint return shall, for the purpose of the computation of the tax in respect of such joint return, be deemed to have ended on the date of the closing of the surviving spouse's taxable year.

(d) Computation of optional tax. For computation of optional tax in the case of a joint return or the return of a surviving spouse, see section 3 and the regulations thereunder.

(e) Change in rates. For treatment of taxable years during which a change in the tax rates occurs see section 21 and the regulations thereunder.

[T.D. 7117, 36 FR 9398, May 25, 1971]