[Code of Federal Regulations]
[Title 26, Volume 1]
[Revised as of April 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 26CFR1.21-1]

[Page 28-36]
 
                       TITLE 26--INTERNAL REVENUE
 
     CHAPTER I--INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY
 
PART 1--INCOME TAXES--Table of Contents
 
Sec. 1.21-1  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is increased or decreased, or any such tax is repealed, and (2) the 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.

[[Page 29]]

    (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--
    (1) An amount which bears the same ratio to the tentative tax 
computed at the rate applicable to the period within the taxable year 
before the effective date of the change that the number of days in such 
period bears to the number of days in the taxable year, and
    (2) An amount which bears the same ratio to the tentative tax 
computed at the rate applicable to the period within the taxable year on 
and after the effective date of the change that the number of days in 
such period bears to the number of days in the taxable year.
    (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.
    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.
    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

[[Page 30]]

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)(1) Section 21 is applicable only if the rate of tax imposed by 
chapter 1 changes. Sections in which rates of tax are specified or 
incorporated by reference include the following: 1, 2, 3, 11, 511, 531, 
541, 821, 831, 871, 881, 1201, and 1348 (for taxable years beginning 
after December 31, 1970). Except as provided in subparagraph (3) of this 
paragraph, section 21 is not applicable with respect to changes in the 
law relating to deductions from gross income, exclusions from or 
inclusions in gross income, or other items taken into account in 
determining the amount or character of income subject to tax. Moreover, 
section 21 is not applicable with respect to changes in the law relating 
to credits against the tax or with respect to changes in the law 
relating to limitations on the amount of tax. Section 21 is applicable, 
however, to all those computations specified in the section providing 
the rate of tax which are implicit in determining the rate. For example, 
if one of the tax brackets in the tax tables under section 3 were to be 
changed, section 21 would be applicable to that change. Thus, if the 
bracket relating to ``at least $4,200 but not less than $4,250'' for 
heads of households should be changed to increase or decrease the last 
sum specified, with corresponding changes being made in subsequent 
brackets, section 21 would be applicable. The enactment of sections 1561 
and 1562 is considered a change in section 11(d) which constitutes a 
change in rate for the period ending after December 31, 1963. The 
amendment of section 1561 and the repeal of section 1562 by the Tax 
Reform Act of 1969 is considered a change in section 11(d) which 
constitutes a change in rate for the period ending after December 31, 
1974. The repeal of the 2 percent additional tax imposed under section 
1503 on corporations filing consolidated returns constitutes a change in 
rate for the period ending after December 31, 1963. The addition to the 
Code of section 1348 (relating to 50 percent maximum rate on earned 
income) is a change in rate to which section 21(a) is applicable. The 
amendment of section 11(d) by the Tax Reduction Act of 1975 which 
increases to $50,000 the surtax exemption for a taxable year ending 
during 1975 constitutes a change in rate for such portion of the taxable 
year (if less than the entire taxable year) as follows December 31, 
1974. Similarly, the return of the surtax exemption to $25,000 for a 
taxable year ending during 1976 constitutes a change in rate for such 
portion of the taxable year (if less than the entire taxable year) as 
follows December 31, 1975.
    (2) Ordinarily, both the old and the new rates are applied to the 
same amount of taxable income. However, where the rate of tax is itself 
taken into account in determining taxable income (for example, the 
special deduction for Western Hemisphere trade corporations under 
section 922), the taxable income used in determining the tentative tax 
employing the rate before the effective date of change shall be 
determined by reference to that rate of tax, and the taxable income for 
the

[[Page 31]]

purpose of determining the tentative tax employing the rate for the 
period on and after the effective date of the change shall be determined 
by reference to the new tax rate.
    (3) Section 21 is applicable with respect to changes in the law 
relating to the standard deduction for individuals provided in part IV 
of subchapter B and to the deduction for personal exemptions for 
individuals provided in part V of subchapter B.
    (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)(1) If a change in the rate of one tax imposed by chapter 1 of 
the Code does not affect the amount of other taxes imposed by chapter 1 
of the Code the other taxes may be determined without regard to section 
21 and section 21 will be applied only to the tax for which a change in 
rate is made. However, if the change of rate of one tax does affect the 
amount of other taxes imposed under chapter 1 of the Code, then the 
computation of the taxes under chapter 1 of the Code so affected shall 
be made by applying section 21. For example, if section 1201 applies to 
an individual taxpayer for a taxable year containing the effective date 
of a change in a rate of tax provided in section 1, then under section 
21 the taxpayer must compute a tentative tax for each period for which a 
different rate of tax is effective under section 1. The tentative tax 
for each such period as computed under section 1201 will reflect the 
rate of tax provided by section 1 for such period.
    (2) In certain cases chapter 1 of the Code provides that the 
particular tax to be imposed upon the taxpayer shall be one of several 
taxes, the basis of selection being the tax that is greater or lesser. 
See, for example, sections 821 and 1201. If in any such case the rate of 
any one of these taxes changes, then the tentative taxes computed as 
provided by section 21 for each period shall be computed employing the 
tax selected in accordance with the general rule of selection for such a 
case, at the rate of tax in effect for such period. Thus, if a change in 
the rate of the alternative tax under section 1201 is such that the 
alternative tax under section 1201 is applicable if the old rate is used 
and is not applicable if the new rate is used, one tentative tax will 
consist of the alternative tax under section 1201 and the other 
tentative tax will consist of the tax imposed by the other applicable 
sections of chapter 1 of the Code. The two tentative taxes so computed 
are then prorated in accordance with section 21(a)(2) and the sum of the 
proportionate amounts is the tax imposed for the taxable year under 
chapter 1 of the Code. See the examples in paragraph (n) of this 
section.
    (k) Section 21 does not apply in the following situations:
    (1) The provisions of section 21 do not apply to the imposition of 
the tax surcharge by section 51. The proration rules of section 51(a) 
apply in the case of a taxable year ending on or after the effective 
date of the surcharge and beginning before July 1, 1970.
    (2) The provisions of section 21 do not apply to the imposition of 
the minimum tax for tax preferences by section 56. The proration rules 
of section 301(c) of the Tax Reform Act of 1969 (83 Stat. 586) apply in 
the case of a taxable year beginning in 1969 and ending in 1970.
    (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

[[Page 32]]

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 Sec. 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:




                              Tentative Tax
Taxable income exclusive of capital      $50,000
 gains and losses...................
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        37,690
 rates).............................
                                     =============
           Alternative Tax Under Section 1201(b) (1969 Rates)
Taxable income ($50,000+50% of           $87,500
 $75,000)...........................
Less 50% of long-term capital gain..      37,500
                                     -------------
Taxable income exclusive of capital       50,000
 gains..............................
                                     =============
Partial tax (tax on $50,000)........      17,060
Plus 25% of $75,000.................      18,750
                                     -------------
Alternative tax under section             35,810
 1201(b) at 1969 rates..............
           Alternative Tax Under Section 1201(b) (1970 Rates)
                                 step i
Taxable income ($50,000 + 50% of         $87,500
 $75,000)...........................
Deduct 50% of net section 1201 gain       37,500
 (net capital gain for taxable years
 beginning after December 31, 1976).
                                     ------------
                                          50,000
                                     ============
Tax on $50,000 (taxable income        ..........     $17,060
 exclusive of capital gains)........
                                 step ii
(a) Net section 1201 gain (net            75,000
 capital gain for taxable years
 beginning after December 31, 1976).
(b) Subsection (d) gain.............      50,000
25% of $50,000 (lesser of (a) or      ..........      12,500
 (b))...............................
                                step iii
(c) 29\1/2\% of $25,000 (excess of         7,375
 (a) over (b))......................
                                     ============
(d) Ordinary income.................     $50,000
50% of net section 1201 gain (net         37,500
 capital gain for taxable years
 beginning after December 31, 1976).
                                     ------------
                                          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)        36,780
 at rates effective on and after
 January 1, 1970....................
                                     =============



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

[[Page 33]]

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 Sec.  1.51-1(d)(1)(i))...................    2,729.28
                                                             -----------
      Total tax for the taxable year........................   39,020.29


    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:

                           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     4,697.50
 effective on or after January 1, 1970..........
                                                 =============

                           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     3,949.00
 effective on or after Januray 1, 1971..........
                                                 =============
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 Sec.  1.51-1(d)(1)(i)).......       56.26
                                                 -------------
      Total tax for the taxable year............    4,569.20
                                                 =============


    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:

                           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     1,886.00
 effective on or after January 1, 1969..........
                                                 =============
                           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     1,737.50
 effective on or after January 1, 1970..........
                                                 =============
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 Sec.  1.51-1(d)(1)(i)).......      104.05
                                                 -------------
  Total tax for the taxable year................    1,891.19
                                                 =============


    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:




                           1970 Tentative Tax
Adjusted gross income...................     $250,000.00
  Less:
    Itemized deductions.................      $34,000.00

[[Page 34]]


    Personal exemption..................          625.00       34,625.00
                                         -------------------------------
Taxable income under 1970 deduction           215,375.00
 provisions.............................
                                         =================
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          136,252.50
 provisions effective on or after
 January 1, 1970........................
                                         =================
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 +      137,127.25
       $874.75).........................
                                         =================
                           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           215,350.00
 provisions.............................
                                         =================
(a) Tax on highest amount of taxable           20,190.00
 income on which rate does not exceed 60
 percent ($50,000) (1971 rates).........
(b) Earned taxable
  income:
  ($215,350x
  $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          7,041.60
 exceeds $50,000........................
(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),       133,565.56
 and (f)) at rates and deduction
 provisions effective on or after
 January 1, 1971........................
                                         =================
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 +        134,709.00
     $1,143.44).........................
                                         =================
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
                                         =================


    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:




                           1963 Tentative Tax
Taxable income..........................        $100,000
                                         =================
Normal tax on $100,000 (1963 rates) 30           $30,000
 percent of $100,000....................
Surtax on $75,000 (1963 rates and                 16,500
 $25,000 surtax exemption) 22 percent of
 $75,000................................
                                         -----------------
      Total tentative tax at rates and            46,500
       surtax exemption effective before
       January 1, 1964..................
                                         =================
                           1964 Tentative Tax
Taxable income..........................        $100,000
                                         =================
Normal tax on $100,000 (1964 rates) 22           $22,000
 percent of $100,000....................

[[Page 35]]


Surtax on $95,000 (1964 rates and a               26,600
 $5,000 surtax exemption) 28 percent of
 $95,000................................
                                         ----------------
      Total tentative tax at rates and            48,600
       surtax exemption effective after
       January 1, 1964..................
                                         =================
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           $22,000
 percent of $100,000....................
Surtax on $95,000 (1964 rates and a               26,600
 $5,000 surtax exemption) 28 percent of
 $95,000................................
                                         -----------------
      Total tentative tax at the 1964             48,600
       rates............................
                                         =================
                           1965 Tentative Tax
Taxable income..........................        $100,000
                                         =================
Normal tax on $100,000 (1965 rates) 22           $22,000
 percent of $100,000....................
Surtax on $95,000 (1965 rates and a               24,700
 $5,000 surtax exemption) 26 percent of
 $95,000................................
                                         ----------------
      Total tentative tax at the 1965             46,700
       rates............................
                                         =================
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
                                         =================


    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:




                           1963 Tentative Tax
Taxable income..........................        $100,000
                                         =================
Normal tax on $100,000 (1963 rates) 30           $30,000
 percent of $100,000....................
Surtax on $75,000 (1963 rates and                 16,500
 $25,000 surtax exemption) 22 percent of
 $75,000................................
                                         ----------------
      Total tentative tax at rates and            46,500
       surtax exemption effective before
       January 1, 1964..................
                                         =================
                           1964 Tentative Tax
Taxable income..........................        $100,000
                                         =================
Normal tax on $100,000 (1964 rates) 22           $22,000
 percent of $100,000....................
Surtax on $75,000 (1964 rates and                 21,000
 $25,000 surtax exemption) 28 percent of
 $75,000................................
Additional tax on $25,000 6 percent of             1,500
 $25,000................................
                                         ----------------
      Total tentative tax at rates and            44,500
       surtax exemption effective on and
       after January 1, 1964............
                                         =================
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
                                         =================


    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:




                           1975 Tentative Tax
Taxable income..........................        $100,000
                                         =================
  Normal tax on $100,000 (1975 rates) 20          $5,000
   percent of $25,000...................
  22 percent of $75,000.................          16,500
  Surtax on $50,000 (1975 rates and               13,000
   $50,000 surtax exemption) 26 percent
   of $50,000...........................
                                         ----------------

[[Page 36]]


      Total tentative tax at rates and            34,500
       surtax exemption effective on and
       after January 1, 1975............
                                         =================
                           1976 Tentative Tax
Taxable income..........................        $100,000
                                         =================
  Normal tax on $100,000 (1976 rates) 22         $22,000
   percent of $100,000..................
  Surtax on $75,000 (1976 rates and               19,500
   $25,000 surtax exemption) 26 percent
   of $75,000...........................
                                         ----------------
      Total tentative tax at rates and            41,500
       surtax exemption effective on and
       after January 1, 1976............
                                         =================
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]