
From the U.S. Code Online via GPO Access
[wais.access.gpo.gov]
[Laws in effect as of January 2, 2001]
[Document affected by Public Law 107-16 Section 101(c)(3)]
[CITE: 26USC15]

 
                     TITLE 26--INTERNAL REVENUE CODE
 
                        Subtitle A--Income Taxes
 
                  CHAPTER 1--NORMAL TAXES AND SURTAXES
 
              Subchapter A--Determination of Tax Liability
 
            PART III--CHANGES IN RATES DURING A TAXABLE YEAR
 
Sec. 15. Effect of changes


(a) General rule

    If any rate of tax imposed by this chapter changes, and if the 
taxable year includes the effective date of the change (unless that date 
is the first day of the taxable year), then--
        (1) tentative taxes shall be computed by applying the rate for 
    the period before the effective date of the change, and the rate for 
    the period on and after such date, to the taxable income for the 
    entire taxable year; and
        (2) the tax for such taxable year shall be the sum of that 
    proportion of each tentative tax which the number of days in each 
    period bears to the number of days in the entire taxable year.

(b) Repeal of tax

    For purposes of subsection (a)--
        (1) if a tax is repealed, the repeal shall be considered a 
    change of rate; and
        (2) the rate for the period after the repeal shall be zero.

(c) Effective date of change

    For purposes of subsections (a) and (b)--
        (1) if the rate changes for taxable years ``beginning after'' or 
    ``ending after'' a certain date, the following day shall be 
    considered the effective date of the change; and
        (2) if a rate changes for taxable years ``beginning on or 
    after'' a certain date, that date shall be considered the effective 
    date of the change.

(d) Section not to apply to inflation adjustments

    This section shall not apply to any change in rates under subsection 
(f) of section 1 (relating to adjustments in tax tables so that 
inflation will not result in tax increases).

(e) References to highest rate

    If the change referred to in subsection (a) involves a change in the 
highest rate of tax imposed by section 1 or 11(b), any reference in this 
chapter to such highest rate (other than in a provision imposing a tax 
by reference to such rate) shall be treated as a reference to the 
weighted average of the highest rates before and after the change 
determined on the basis of the respective portions of the taxable year 
before the date of the change and on or after the date of the change.

(Aug. 16, 1954, ch. 736, 68A Stat. 12, Sec. 21; Pub. L. 88-272, title I, 
Sec. 132, Feb. 26, 1964, 78 Stat. 30; Pub. L. 91-172, title VIII, 
Sec. 803(e), Dec. 30, 1969, 83 Stat. 685; Pub. L. 92-178, title II, 
Sec. 205, Dec. 10, 1971, 85 Stat. 511; Pub. L. 94-12, title III, 
Sec. 305(b)(2), Mar. 29, 1975, 89 Stat. 45; Pub. L. 94-164, 
Sec. 4(d)(2), Dec. 23, 1975, 89 Stat. 975; Pub. L. 94-455, title IX, 
Sec. 901(c)(2), Oct. 4, 1976, 90 Stat. 1607; Pub. L. 95-30, title I, 
Sec. 101(d)(2), May 23, 1977, 91 Stat. 133; Pub. L. 95-600, title I, 
Sec. 106, Nov. 6, 1978, 92 Stat. 2776; Pub. L. 97-34, title I, 
Sec. 101(d)(3), Aug. 13, 1981, 95 Stat. 184; renumbered Sec. 15, Pub. L. 
98-369, div. A, title IV, Sec. 474(b)(1), July 18, 1984, 98 Stat. 830; 
Pub. L. 99-514, title I, Sec. 101(b), Oct. 22, 1986, 100 Stat. 2099; 
Pub. L. 100-647, title I, Sec. 1006(a), Nov. 10, 1988, 102 Stat. 3393.)


                               Amendments

    1988--Subsec. (e). Pub. L. 100-647 added subsec. (e).
    1986--Subsec. (d). Pub. L. 99-514 amended subsec. (d) generally, 
substituting ``apply to inflation adjustments'' for ``apply to section 1 
rate changes made by Economic Recovery Tax Act of 1981'' in heading and 
struck out ``section 1 attributable to the amendments made by section 
101 of the Economic Tax Act of 1981 or'' before ``subsection (f)'' in 
text.
    1984--Pub. L. 98-369 renumbered section 21 of this title as this 
section.
    1981--Subsec. (d). Pub. L. 97-34 substituted provisions that this 
section shall not apply to any change in rates under section 1 
attributable to the amendments made by section 101 of the Economic 
Recovery Tax Act of 1981 or subsec. (f) of section 1 for provisions that 
had related to the changes made by section 303(b) of the Tax Reduction 
Act of 1975 in the surtax exemption.
    Subsecs. (e), (f). Pub. L. 97-34 struck out subsecs. (e) and (f) 
which had related, respectively, to changes made by the Tax Reduction 
and Simplification Act of 1977 and to changes made by Revenue Act of 
1978.
    1978--Subsec. (f). Pub. L. 95-600 added subsec. (f).
    1977--Subsec. (d). Pub. L. 95-30, Sec. 101(d)(2)(A), (B), 
redesignated subsec. (f) as (d). Former subsec. (d), which directed 
that, in applying subsec. (a) to a taxable year of an individual which 
was not a calendar year, each change made by the Tax Reform Act of 1969 
in part I or in the application of part IV or V of subchapter B for 
purposes of the determination of taxable income should be treated as a 
change in a rate of tax, was struck out.
    Subsec. (e). Pub. L. 95-30, Sec. 101(d)(2)(A), (C), added subsec. 
(e). Former subsec. (e), which directed that, in applying subsec. (a) to 
a taxable year of an individual which was not a calendar year, each 
change made by the Revenue Act of 1971 in section 141 (relating to the 
standard deduction) and section 151 (relating to personal exemptions) 
should be treated as a change in a rate of tax, was struck out.
    Subsec. (f). Pub. L. 95-30, Sec. 101(d)(2)(B), redesignated subsec. 
(f) as (d).
    1976--Subsec. (f). Pub. L. 94-455 substituted ``in the surtax 
exemption and any change under section 11(d) in the surtax exemption'' 
for ``and the change made by section 3(c) of the Revenue Adjustment Act 
of 1975 in section 11(d) (relating to corporate surtax exemption)''.
    1975--Subsec. (f). Pub. L. 94-164 inserted reference to change made 
by section 3(c) of the Revenue Adjustment Act of 1975.
    Pub. L. 94-12 added subsec. (f).
    1971--Subsec. (e). Pub. L. 92-178 added subsec. (e).
    1969--Subsec. (d). Pub. L. 91-172 substituted provisions covering 
changes made by the Tax Reform Act of 1969 in case of individuals for 
provisions covering changes made by Revenue Act of 1964.
    1964--Subsec. (d). Pub. L. 88-272 amended subsection generally by 
substituting provisions relating to changes made by the Revenue Act of 
1964, for provisions relating to taxable years beginning before Jan. 1, 
1954, and ending after Dec. 31, 1953.


                    Effective Date of 1988 Amendment

    Amendment by Pub. L. 100-647 effective, except as otherwise 
provided, as if included in the provision of the Tax Reform Act of 1986, 
Pub. L. 99-514, to which such amendment relates, see section 1019(a) of 
Pub. L. 100-647, set out as a note under section 1 of this title.


                    Effective Date of 1986 Amendment

    Amendment by Pub. L. 99-514 applicable to taxable years beginning 
after Dec. 31, 1986, see section 151(a) of Pub. L. 99-514, set out as a 
note under section 1 of this title.


                    Effective Date of 1981 Amendment

    Amendment by Pub. L. 97-34 applicable to taxable years beginning 
after Dec. 31, 1981, see section 101(f)(1) of Pub. L. 97-34, set out as 
a note under section 1 of this title.


                    Effective Date of 1977 Amendment

    Amendment by Pub. L. 95-30 applicable to taxable years beginning 
after Dec. 31, 1976, see section 106(a) of Pub. L. 95-30, set out as a 
note under section 1 of this title.


                    Effective Date of 1976 Amendment

    Amendment by Pub. L. 94-455 applicable with respect to taxable years 
ending after Dec. 31, 1975, see section 901(d) of Pub. L. 94-455, set 
out as a note under section 11 of this title.


                    Effective Date of 1975 Amendment

    Amendment by Pub. L. 94-164 applicable to taxable years beginning 
after Dec. 31, 1975, see section 4(e) of Pub. L. 94-164, set out as an 
Effective and Termination Dates of 1975 Amendments note under section 11 
of this title.


                    Effective Date of 1964 Amendment

    Section 132 of Pub. L. 88-272 provided that the amendment made by 
that section is effective with respect to taxable years ending after 
Dec. 31, 1963.


             Coordination of 1997 Amendment With Section 15

    Pub. L. 105-34, title I, Sec. 1(c), Aug. 5, 1997, 111 Stat. 788, 
provided that: ``No amendment made by this Act [see Tables for 
classification] shall be treated as a change in a rate of tax for 
purposes of section 15 of the Internal Revenue Code of 1986.''


             Coordination of 1993 Amendment With Section 15

    Pub. L. 103-66, title XIII, Sec. 13001(c), Aug. 10, 1993, 107 Stat. 
416, provided that: ``Except in the case of the amendments made by 
section 13221 [amending sections 11, 852, 1201, and 1445 of this title] 
(relating to corporate rate increase), no amendment made by this chapter 
[chapter 1 (Secs. 13001-13444) of title XIII of Pub. L. 103-66, see 
Tables for classification] shall be treated as a change in a rate of tax 
for purposes of section 15 of the Internal Revenue Code of 1986.''


             Coordination of 1990 Amendment With Section 15

    Pub. L. 101-508, title XI, Sec. 11001(c), Nov. 5, 1990, 104 Stat. 
1388-400, provided that: ``Except as otherwise expressly provided in 
this title, no amendment made by this title [see Tables for 
classification] shall be treated as a change in a rate of tax for 
purposes of section 15 of the Internal Revenue Code of 1986.''


             Coordination of 1987 Amendment With Section 15

    Pub. L. 100-203, title X, Sec. 10000(c), Dec. 22, 1987, 101 Stat. 
1330-382, provided that: ``No amendment made by this title [see Tables 
for classification] shall be treated as a change in a rate of tax for 
purposes [of] section 15 of the Internal Revenue Code of 1986.''


             Coordination of 1986 Amendment With Section 15

    Section 3(b) of Pub. L. 99-514 provided that:
    ``(1) In general.--Except as provided in paragraph (2), for purposes 
of section 15 of the Internal Revenue Code of 1986, no amendment or 
repeal made by this Act [see Tables for classification] shall be treated 
as a change in the rate of a tax imposed by chapter 1 of such Code.
    ``(2) Exception.--Paragraph (1) shall not apply to the amendment 
made by section 601 [amending section 11 of this title] (relating to 
corporate rate reductions).''

                  Section Referred to in Other Sections

    This section is referred to in sections 59A, 441, 6013 of this 
title.
