Treasury Regulations · 26 CFR
§ 1.15-1. Changes in rate during a taxable year.
Regulation text, no changes From the eCFR, current as of October 15, 2026. The eCFR is an authoritative but unofficial editorial compilation of the Code of Federal Regulations; the official text is the annual CFR on govinfo. Compare it with this section on ecfr.gov (external site) or the official annual CFR on govinfo (external site).
Regulation under 26 U.S.C. § 15
Cite as 26 CFR § 1.15-1
At a glance
Read from the text and its source citation. Not part of the regulation.
- Status
- In the current eCFR
- Issued
- November 26, 1960 by T.D. 6500
- Last amended
- August 14, 2007 by T.D. 9354
- Issued under
- 26 U.S.C. § 15
- Length
- 5,259 words · about 23 min to read
- Cross-references
- cites 16 Code sections and 1 regulation; cited by 0
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.
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.
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.
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:
| Tentative Tax | |||
| Taxable income exclusive of capital gains and losses | $50,000 | ||
| Long-term capital gain | 75,000 | ||
| 125,000 | |||
| Deduct 50% of long-term capital gain | 37,500 | ||
| Taxable income | 87,500 | ||
| Tax under section 1 (1969 and 1970 rates) | 37,690 | ||
| Alternative Tax Under Section 1201(b) (1969 R ates) | |||
| Taxable income ($50,000 + 50% of $75,000) | $87,500 | ||
| Less 50% of long-term capital gain | 37,500 | ||
| Taxable income exclusive of capital gains | 50,000 | ||
| Partial tax (tax on $50,000) | 17,060 | ||
| Plus 25% of $75,000 | 18,750 | ||
| Alternative tax under section 1201(b) at 1969 rates | 35,810 | ||
| Alternative Tax Under Section 1201(b) (1970 Rates) | |||
| step i | |||
| Taxable income ($50,000 + 50% of $75,000) | $87,500 | ||
| Deduct 50% of net section 1201 gain (net capital gain for taxable years beginning after December 31, 1976) | 37,500 | ||
| 50,000 | |||
| Tax on $50,000 (taxable income exclusive of capital gains) | $17,060 | ||
| step ii | |||
| (a) Net section 1201 gain (net capital gain for taxable years beginning after December 31, 1976) | 75,000 | ||
| (b) Subsection (d) gain | 50,000 | ||
| 25% of $50,000 (lesser of (a) or (b)) | 12,500 | ||
| step iii | |||
| (c) 291⁄2% of $25,000 (excess of (a) over (b)) | 7,375 | ||
| (d) Ordinary income | $50,000 | ||
| 50% of net section 1201 gain (net capital gain for taxable years beginning after December 31, 1976) | 37,500 | ||
| 87,500 | |||
| Tax on $87,500 | $37,690 | ||
| Ordinary income | $50,000 | ||
| 50% of subsection (d) gain | 25,000 | ||
| 75,000 | |||
| Tax on $75,000 | 30,470 | ||
| Difference | 7,220 | ||
| Lesser of (c) or (d) | $7,220 | ||
| Alternative tax (total of 3 steps) at rates effective on and after January 1, 1970 | 36,780 | ||
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:
| 1969—184/365 of $35,810 | $18,052.16 |
| 1970—181/365 of $36,780 | 18,238.85 |
| 36,291.01 | |
| Tax surcharge (See § 1.51-1(d)(1)(i)) | 2,729.28 |
| Total tax for the taxable year | 39,020.29 |
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:
| 1970 Tentative Tax | ||
| Adjusted gross income | $18,500.00 | |
| Less: | ||
| Standard deduction | $1,000.00 | |
| Personal exemption | 625.00 | 1,625.00 |
| Taxable income under 1970 deduction provisions | 16,875.00 | |
| Tax on $16,875 (1970 rates): | ||
| Tax on first $16,000 | 4,330.00 | |
| 42 percent of $875 | 367.50 | |
| Tentative tax at rates and deduction provisions effective on or after January 1, 1970 | 4,697.50 | |
| 1971 Tentative Tax | ||
| Adjusted gross income | $18,500.00 | |
| Less: | ||
| Standard deduction | $1,500 | |
| Personal exemption | 650 | 2,150.00 |
| Taxable income under 1971 deduction provisions | 16,350.00 | |
| Tax on $16,350 (1971 rates): | ||
| Tax on first $16,000 | 3,830 | |
| 34 percent of $350 | 119 | |
| Tentative tax at rates and deduction provisions effective on or after Januray 1, 1971 | 3,949.00 | |
| The 1970 and 1971 tentative taxes are apportioned as follows: | ||
| 1970—275/365 of $4,697.50 | 3,539.21 | |
| 1971—90/365 of $3,949.00 | 973.73 | |
| 4,512.94 | ||
| Tax surcharge (see § 1.51-1(d)(1)(i)) | 56.26 | |
| Total tax for the taxable year | 4,569.20 | |
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:
| 1969 Tentative Tax | ||
| Adjusted gross income | $12,500.00 | |
| Less: | ||
| Standard deduction | $1,000.00 | |
| Personal exemption (2) | 1,200.00 | 2,200.00 |
| Taxable income under 1969 deduction provisions | 10,300.00 | |
| Taxable income reduced by one-half | 5,150.00 | |
| Tax on $5,150 (1969 rates): | ||
| Tax on first $4,000 | $690.00 | |
| 22 percent of $1,150 | 253.00 | 943.00 |
| Twice the tax on $5,150 | $1,886.00 | |
| Tentative tax at rates and deduction provisions effective on or after January 1, 1969 | 1,886.00 | |
| 1970 Tentative Tax | ||
| Adjusted gross income | $12,500.00 | |
| Less: | ||
| Standard deduction | $1,000.00 | |
| Personal exemption (3) | 1,875.00 | 2,875.00 |
| Taxable income under 1970 deduction provisions | $9,625.00 | |
| Tax on $9,625 (1970 rates): | ||
| Tax on first $8,000 | $1,380.00 | |
| 22 percent of $1,625 | 357.50 | |
| Tentative tax at rates and deduction provisions effective on or after January 1, 1970 | 1,737.50 | |
| The 1969 and 1970 tentative taxes are apportioned as follows: | ||
| 1969—122/365 of $1,886 | $630.39 | |
| 1970—243/365 of $1,737.50 | 1,156.75 | |
| 1,787.14 | ||
| Tax surcharge (see § 1.51-1(d)(1)(i)) | 104.05 | |
| Total tax for the taxable year | 1,891.19 | |
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:
| 1970 Tentative Tax | ||
| Adjusted gross income | $250,000.00 | |
| Less: | ||
| Itemized deductions | $34,000.00 | |
| Personal exemption | 625.00 | 34,625.00 |
| Taxable income under 1970 deduction provisions | 215,375.00 | |
| Tax on $215,375 (1970 rates) | ||
| Tax on first $100,000 | $55,490.00 | |
| 70 percent of $115,375 | 80,762.50 | |
| Tentative tax at rates and deduction provisions effective on or after January 1, 1970 | 136,252.50 | |
| Minimum tax: | ||
| Total tax preference items | 175,000.00 | |
| Less: | ||
| Exemption | $30,000.00 | |
| Income tax | 136,252.50 | 166,252.50 |
| Subject to 10 percent tax | 8,747.50 | |
| 10 percent tax | 874.75 | |
| Total tentative tax ($136,252.50 + $874.75) | 137,127.25 | |
| 1971 Tentative Tax | ||
| Adjusted gross income | $250,000.00 | |
| Less: | ||
| Itemized deductions | $34,000.00 | |
| Personal exemption | 650.00 | 34,650.00 |
| Taxable income under 1971 deduction provisions | 215,350.00 | |
| (a) Tax on highest amount of taxable income on which rate does not exceed 60 percent ($50,000) (1971 rates) | 20,190.00 | |
| (b) Earned taxable | ||
| income: | ||
| ($215,350 × | ||
| $240,000/ | ||
| $250,000) | $206,736.00 | |
| Less: Tax | ||
| preference offset: | ||
| ($175,000 | ||
| −$30,000) | 145,000.00 | |
| 61,736.00 | ||
| (c) 60% of the amount by which $61,736 exceeds $50,000 | 7,041.60 | |
| (d) Tax on $215,350 (1971 rates) | ||
| Tax on first $100,000 | 53,090.00 | |
| 70% of $115,350 | 80,745.00 | |
| Total | 133,835.00 | |
| (e) Tax on $61,736 (1971 rates) | ||
| Tax on first $60,000 | 26,390.00 | |
| 64% of $1,736 | 1,111.04 | |
| Total | 27,501.04 | |
| (f) Excess of $133,835 over $27,501.04 | 106,333.96 | |
| Tentative tax (total of Steps (a), (c), and (f)) at rates and deduction provisions effective on or after January 1, 1971 | 133,565.56 | |
| Minimum tax: | ||
| Total tax preference items | 175,000.00 | |
| Less: | ||
| Exemption | $30,000.00 | |
| Income tax | 133,565.56 | 163,565.56 |
| Subject to 10 percent tax | $11,434.44 | |
| 10 percent tax | 1,143.44 | |
| Total tentative tax ($133,565.56 + $1,143.44) | 134,709.00 | |
| The 1970 and 1971 tentative taxes are apportioned as follows: | ||
| 1970—184/365 of $137,127.25 | 69,127.16 | |
| 1971—181/365 of $134,709 | 66,800.90 | |
| Total tax for the taxable year | 135,928.06 | |
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:
| 1963 Tentative Tax | ||
| Taxable income | $100,000 | |
| Normal tax on $100,000 (1963 rates) 30 percent of $100,000 | $30,000 | |
| Surtax on $75,000 (1963 rates and $25,000 surtax exemption) 22 percent of $75,000 | 16,500 | |
| Total tentative tax at rates and surtax exemption effective before January 1, 1964 | 46,500 | |
| 1964 Tentative Tax | ||
| Taxable income | $100,000 | |
| Normal tax on $100,000 (1964 rates) 22 percent of $100,000 | $22,000 | |
| Surtax on $95,000 (1964 rates and a $5,000 surtax exemption) 28 percent of $95,000 | 26,600 | |
| Total tentative tax at rates and surtax exemption effective after January 1, 1964 | 48,600 | |
| The 1963 and 1964 tentative taxes are apportioned as follows: | ||
| 1963—275/366 of $46,500 | 34,938.52 | |
| 1964—91/366 of $48,600 | 12,083.61 | |
| Total tax for the taxable year | 47,022.13 | |
| M has the same amount of taxable income in 1965. Its income tax liability for the fiscal year ending March 31, 1965, is computed as follows: | ||
| 1964 Tentative Tax | ||
| Taxable income | $100,000 | |
| Normal tax on $100,000 (1964 rates) 22 percent of $100,000 | $22,000 | |
| Surtax on $95,000 (1964 rates and a $5,000 surtax exemption) 28 percent of $95,000 | 26,600 | |
| Total tentative tax at the 1964 rates | 48,600 | |
| 1965 Tentative Tax | ||
| Taxable income | $100,000 | |
| Normal tax on $100,000 (1965 rates) 22 percent of $100,000 | $22,000 | |
| Surtax on $95,000 (1965 rates and a $5,000 surtax exemption) 26 percent of $95,000 | 24,700 | |
| Total tentative tax at the 1965 rates | 46,700 | |
| The 1964 and 1965 tentative taxes are apportioned as follows: | ||
| 1964—275/365 of $48,600 | $36,616.44 | |
| 1965—90/365 of $46,700 | 11,515.07 | |
| Total tax for the taxable year | 48,131.51 | |
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:
| 1963 Tentative Tax | ||
| Taxable income | $100,000 | |
| Normal tax on $100,000 (1963 rates) 30 percent of $100,000 | $30,000 | |
| Surtax on $75,000 (1963 rates and $25,000 surtax exemption) 22 percent of $75,000 | 16,500 | |
| Total tentative tax at rates and surtax exemption effective before January 1, 1964 | 46,500 | |
| 1964 Tentative Tax | ||
| Taxable income | $100,000 | |
| Normal tax on $100,000 (1964 rates) 22 percent of $100,000 | $22,000 | |
| Surtax on $75,000 (1964 rates and $25,000 surtax exemption) 28 percent of $75,000 | 21,000 | |
| Additional tax on $25,000 6 percent of $25,000 | 1,500 | |
| Total tentative tax at rates and surtax exemption effective on and after January 1, 1964 | 44,500 | |
| The 1963 and 1964 tentative taxes are apportioned as follows: | ||
| 1963—275/366 of $46,500 | $34,938.52 | |
| 1964—91/366 of $44,500 | 11,064.21 | |
| Total tax for the taxable year | 46,002.73 | |
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:
| 1975 Tentative Tax | ||
| Taxable income | $100,000 | |
| Normal tax on $100,000 (1975 rates) 20 percent of $25,000 | $5,000 | |
| 22 percent of $75,000 | 16,500 | |
| Surtax on $50,000 (1975 rates and $50,000 surtax exemption) 26 percent of $50,000 | 13,000 | |
| Total tentative tax at rates and surtax exemption effective on and after January 1, 1975 | 34,500 | |
| 1976 Tentative Tax | ||
| Taxable income | $100,000 | |
| Normal tax on $100,000 (1976 rates) 22 percent of $100,000 | $22,000 | |
| Surtax on $75,000 (1976 rates and $25,000 surtax exemption) 26 percent of $75,000 | 19,500 | |
| Total tentative tax at rates and surtax exemption effective on and after January 1, 1976 | 41,500 | |
| The 1975 and 1976 tentative taxes are apportioned as follows: | ||
| 1975—184/366 of $34,500 | $17,344 | |
| 1976—182/366 of $41,500 | 20,637 | |
| Total tax for the taxable year | 37,981 | |
(Secs. 1561(a) (83 Stat. 599; 26 U.S.C. 1561(a)) of the Internal Revenue Code)
[T.D. 6500, 25 FR 11402, Nov. 26, 1960; 25 FR 14021, Dec. 31, 1960, as amended by T.D. 7164, 37 FR 4190, Feb. 29, 1972; T.D. 74-13, 41 FR 12639, Mar. 26, 1976; T.D. 7528, 42 FR 64694, Dec. 28, 1977; T.D. 7728, 45 FR 72651, Nov. 3, 1980. Redesignated by T.D. 9354, 72 FR 45341, Aug. 14, 2007]
Cross-references
Computed from the citations in the text of 26 CFR.
Code sections it cites
- § 21 Expenses for household and dependent care services necessary for gainful employment
- § 11 Tax imposed
- § 1562 Repealed
- § 6013 Joint returns of income tax by husband and wife
- § 443 Returns for a period of less than 12 months
- § 441 Period for computation of taxable income
- § 3 Tax tables for individuals
- § 1561 Limitation on accumulated earnings credit in the case of certain controlled corporations
- § 1503 Computation and payment of tax
- § 1348 Repealed
- § 1201 Repealed
- § 1 Tax imposed
- § 51 Amount of credit
- § 31 Tax withheld on wages
- § 152 Dependent defined
- § 57 Items of tax preference
Regulations it cites
Amendment history
From the source citation at the end of the section, newest first. T.D. is a Treasury decision; FR is the Federal Register.
- Amended by T.D. 9354 (72 FR 45341)
- Amended by T.D. 7728 (45 FR 72651)
- Amended by T.D. 7528 (42 FR 64694)
- Amended (41 FR 12639)
- Amended by T.D. 7164 (37 FR 4190)
- Amended (25 FR 14021)
- Issued by T.D. 6500 (25 FR 11402)
Where it sits in 26 CFR
- Subchapter A Income tax
- Part 1 Income taxes
- Changes in Rates During a Taxable Year