Sec. 1.15-1 Changes in rate during a taxable year.

(a) Section 21 applies to all taxpayers, including individuals and corporations. It provides a general rule applicable in any case where (1) any rate of tax imposed by chapter 1 of the Code upon the taxpayer is increased or decreased, or any such tax is repealed, and (2) the taxable year includes the effective date of the change, except where that date is the first day of the taxable year. For example, the normal tax on corporations under section 11(b) was decreased from 30 percent to 22 percent in the case of a taxable year beginning after December 31, 1963. Accordingly, the tax for a taxable year of a corporation beginning on January 1, 1964, would be computed under section 11(b) at the new rate without regard to section 21. However, for any taxable year beginning before January 1, 1964, and ending on or after that date, the tax would be computed under section 21. For additional circumstances under which section 21 is not applicable, see paragraph (k) of this section.

(b) In any case in which section 21 is applicable, a tentative tax shall be computed by applying to the taxable income for the entire taxable year the rate for the period within the taxable year before the effective date of change, and another tentative tax shall be computed by applying to the taxable income for the entire taxable year the rate for the period within the taxable year on or after such effective date. The tax imposed on the taxpayer is the sum of--

(c) If the rate of tax is changed for taxable years "beginning after" or "ending after" a certain date, the following day is considered the effective date of the change for purposes of section 21. If the rate is changed for taxable years "beginning on or after" a certain date, that date is considered the effective date of the change for purposes of section 21. This rule may be illustrated by the following examples:

Example 1. Assume that the law provides that a change in a certain rate of tax shall be effective only with respect to taxable years beginning after December 31, 1969. The effective date of change for purposes of section 21 is January 1, 1970, and section 21 must be applied to any taxable year which begins before and ends on or after January 1, 1970. 4

Example 2. Assume that the law provides that a change in a certain rate of tax shall be applicable only with respect to taxable years ending after December 31, 1970. For purposes of section 21, the effective date of change is January 1, 1971, and section 21 must be applied to any taxable year which begins before and ends on or after January 1, 1971. 4

Example 3. Assume that the law provides that a change in a certain rate of tax shall be effective only with respect to taxable years beginning on or after January 1, 1971. The effective date of change for purposes of section 21 is January 1, 1971, and section 21 must be applied to any taxable year which begins before and ends on or after January 1, 1971.

(d) If a tax is repealed, the repeal will be treated as a change of rate for purposes of section 21, and the rate for the period after the repeal (for purposes of computing the tentative tax with respect to that period) will be considered zero. For example, the Tax Reform Act of 1969 repealed section 1562, which imposed a 6 percent additional tax on controlled corporations electing multiple surtax exemptions, effective for taxable years beginning after December 31, 1974. For such controlled corporations having taxable years beginning in 1974 and ending in 1975, the rate for the period ending before January 1, 1975, would be 6 percent; the rate for the period beginning after December 31, 1974, would be zero. However, subject to the rules stated in this section, section 21 does not apply to the imposition of a new tax. For example, if a new tax is imposed for taxable years beginning on or after July 1, 1972, a computation under section 21 would not be required with respect to such new tax in the case of taxable years beginning before July 1, 1972, and ending on or after that date. If the effective date of the imposition of a new tax and the effective date of a change in rate of such tax fall in the same taxable year, section 21 is not applicable in computing the taxpayer's liability for such tax for such year unless the new tax is expressly imposed upon the taxpayer for a portion of his taxable year prior to the change in rate.

(e) If a husband and wife have different taxable years because of the death of either spouse, and if a joint return is filed with respect to the taxable year of each, then, for purposes of section 21, the joint return shall be treated as if the taxable years of both spouses ended on the date of the closing of the surviving spouse's taxable year. See section 6013 (c), relating to treatment of joint return after death of either spouse. Accordingly, if a change in the rate of tax is effective during the taxable year of the surviving spouse, the tentative taxes with respect to the joint return shall be computed on the basis of the number of days during which each rate of tax was in effect for the taxable year of the surviving spouse.

(f) Section 21 applies whether or not the taxpayer has a taxable year of less than 12 months. Moreover, section 21 applies whether or not the taxable income for a taxable year of less than 12 months is required to be placed on an annual basis under section 443. If the taxable income is required to be computed under section 443(b) then the tentative taxes under section 21 are computed as provided in paragraph (1) or (2) of section 443(b) and are reduced as provided in those paragraphs. The tentative taxes so computed and reduced are then apportioned as provided in section 21(a)(2) to determine the tax for such taxable year as computed under section 21.

(g) If a taxpayer has made the election under section 441(f) (relating to computation of taxable income on the basis of an annual accounting period varying from 52 to 53 weeks), the rules provided in section 441(f)(2) shall be applicable for purposes of determining whether section 21 applies to the taxable year of the taxpayer. Where a taxpayer has made the election under section 441(f) and where section 21 applies to the taxable year of the taxpayer the computation under section 21(a)(2) shall be made upon the basis of the actual number of days in the taxable year and in each period thereof.

(h)

(i) If the rate of tax changes more than once during the taxable year, section 21 is applicable to each change in rate. For example, if the rate of normal tax changed for taxable years beginning on or after March 1, 1954, and changed again for taxable years beginning on or after June 1, 1954, section 21 requires computation of 3 tentative taxes for any taxable year which began before March 1, 1954, and ended on or after June 1, 1954: One tentative tax at the rate in effect before the March 1 change; another tentative tax at the rate in effect from March 1 to May 31; and a third tentative tax at the rate in effect from June 1 to the end of the taxable year. The proportion of each such tentative tax taken into account in determining the tax imposed on the taxpayer is computed by reference to the portion of the taxable year before March 1, 1954, by reference to the portion of the taxable year from March 1, 1954, through May 31, 1954, and by reference to the portion of the taxable year from June 1, 1954, to the end of the taxable year, respectively.

(j)

(k) Section 21 does not apply in the following situations:

(l) In computing the number of days each rate of tax is in effect during the taxable year for purposes of section 21(a)(2), the effective date of the change in rate shall be counted in the period for which the new rate is in effect.

(m) Any credits against tax, and any limitation in any credit against tax, shall be based upon the tax computed under section 21. For credits against tax, see Part IV (section 31 and following), Subchapter A, Chapter 1 of the Code.

(n) The application of section 21 may be illustrated by the following examples: (See also the examples in section 1.1561-2A(a)(3).)

Example 1. A, a married taxpayer filing a joint return, reports his income on the basis of a fiscal year ending June 30. For his fiscal year ending June 30, 1970, A reports taxable income (exclusive of capital gains and losses) of $50,000 and net long-term capital gain (section 1201 gain (net capital gain for taxable years beginning after December 31, 1976)) of $75,000. The rate of tax on capital gains under section 1201(b) relating to the alternative tax has been increased from 25 percent to a maximum rate of 29\1/2\ percent with respect to gain in excess of $50,000 and the effective date of the change in rate is January 1, 1970. The income tax for the taxable year ended June 30, 1970, would be computed under section 21 as follows:

Since the alternative tax is less than the tax imposed under section 1 for both the period in 1969 and the period in 1970, the alternative tax applies for both periods. Thus, since the effective date of the change in the rate of tax on capital gains is January 1, 1970, the old rate of alternative tax is effective for 184 days of the taxable year and the new rate of alternative tax is effective for 181 days of the taxable year. The alternative taxes are apportioned as follows:

Example 2. B, a single individual not a head of a household, has a taxable year ending March 31. For the taxable year ending March 31, 1971, B has adjusted gross income of $18,500. His computation of the tax imposed is as follows:

Example 3. H and W, husband and wife, have a foster child, C, who qualifies as a dependent under section 152(b)(2) for the period beginning after December 31, 1969. H and W file a joint return on the basis of a taxable year ending August 31. For the taxable year ending August 31, 1970, H and W have adjusted gross income of $12,500. Their computation of the tax imposed is as follows:

Example 4. B, a single individual with one exemption, reports his income on the basis of a fiscal year ending June 30. For fiscal year ending June 30, 1971, B reports adjusted gross income of $250,000, consisting of earned net income of $240,000 and investment income of $10,000. In addition, on April 24, 1971, stock was transferred to B pursuant to his exercise of a qualified stock option, and the fair market value of such stock at that time exceeded the option price by $175,000. This $175,000 constitutes an item of tax preference described in section 57(a)(6). B claims itemized deductions in the amount of $34,000. By reason of section 1348, the maximum rate of tax on earned taxable income for a taxable year beginning after 1970 but before 1972 is 60 percent. The income tax for the taxable year ending June 30, 1971, would be computed under section 21 as follows:

Example 5. The surtax exemption of corporation M (one of 4 subsidiary corporations of W corporation), which files its income tax returns on the basis of a fiscal year ending March 31, 1964, is less than $25,000, by reason of section 1561 of the Code applicable to taxable years ending after December 31, 1963, and beginning before January 1, 1975. The taxable income of corporation M is $100,000, and the amount of the surtax exemption determined under the new rule for the 1964 taxable year is $5,000 ($25,000 / 5). M's income tax liability for the taxable year ending March 31, 1964, is computed as follows:

Example 6. Assume the same facts as in example (5), except that M elected the additional tax under section 1562 for its fiscal year ending March 31, 1964. M's tax liability is completed as follows:

Example 7. Corporation N files its income tax returns on the basis of a fiscal year ending June 30. For its taxable year ending in 1976, the taxable income of N is $100,000. N's income tax liability is determined for the period July 1, 1975, through December 31, 1975, by taking into account two rates of normal tax under section 11(b)(2) (A) and (B) and the increase to $50,000 in the surtax exemption under section 11(d). For the period January 1, 1976, through June 30, 1976, N's income tax liability is determined by taking into account the single normal tax rate under section 11(b)(1) and the $25,000 surtax exemption under section 11(d). N's tax liability for the taxable year ending June 30, 1976, is computed as follows: