Missouri Code of State Regulations
Title 12 - DEPARTMENT OF REVENUE
Division 10 - Director of Revenue
Chapter 2 - Income Tax
Section 12 CSR 10-2.030 - Non-Standard Tax Periods, Subsequent Change of Accounting Period, and Personal and Dependency Exemption Deductions

(1) If a taxpayer's taxable year is changed for federal income tax purposes, the Missouri taxable year will automatically be changed. No application for change of accounting period for Missouri income tax purposes will be required. If a short taxable period for federal income tax purposes results from a change in the taxpayer's accounting period, the taxpayer also shall file a Missouri income tax return for that short taxable period.

(2) If there is a short taxable period, Missouri taxable income shall be computed on the basis of the short taxable period for which the return is made and in accordance with the statutory provisions of sections 143.011 to 143.996, RSMo, applicable to the determination of Missouri taxable income generally, except that the amount of deductions allowed by sections 143.151 and 143.161, RSMo, shall be reduced to the amount which bears the same ratio to the full amount for those deductions as the number of months in the short taxable period bears to twelve (12) months.

(3) Pursuant to section 143.151, RSMo, a resident shall generally be allowed a personal exemption deduction of two thousand one hundred dollars ($2,100) for such resident and two thousand one hundred dollars ($2,100) for such resident's spouse if the resident is entitled to a deduction for such personal exemptions for federal income tax purposes. A resident with a Missouri adjusted gross income of less than twenty thousand dollars ($20,000) shall generally be allowed an additional deduction of five hundred dollars ($500) for such resident and an additional five hundred dollars ($500) for such resident's spouse if the resident is entitled to a deduction for such personal exemptions for federal income tax purposes, and the spouse's Missouri adjusted gross income is less than twenty thousand dollars ($20,000). None of the deductions described in sections 143.151, RSMo, or in subsections 1 or 3 of section 143.161, RSMo, shall be allowed for a given tax period if the exemption amount as defined under 26 U.S.C. section 151 is zero (0) for that tax period.

(4) A resident who qualifies as an unmarried head of household or as a surviving spouse for federal income tax purposes may generally deduct an additional one thousand four hundred dollars ($1,400) pursuant to section 143.161.2, RSMo. This additional deduction for a taxpayer who qualifies as an unmarried head of household or a surviving spouse is not dependent on the taxpayer's eligibility for a dependency exemption deduction under section 143.161.1, RSMo.

(5) Example: Tom Taxpayer, a resident individual, has been filing his federal and Missouri income tax returns on the basis of a fiscal year ending September 30. He changes to a calendar year basis and files a federal income tax return for the short taxable period October 1 to December 31. He qualifies as a surviving spouse for federal income tax purposes. For his short taxable period, the exemption amount defined under 26 U.S.C. section 151 is zero (0). He has no federal income tax liability for the tax year. His federal adjusted gross income (FAGI) for the short taxable period is as follows:

(6) A taxpayer which, for federal income tax purposes, has elected to use a taxable year that varies from 52 to 53 weeks is referred to by this rule as "52-53 Week Taxpayer." A 52-53 Week Taxpayer shall determine the effective date or the applicability of any provision of sections 143.011 to 143.996, RSMo, that is expressed in terms of taxable years beginning, including, or ending with reference to a specified date which is the first or last day of a month by treating the taxpayer's 52-53 week taxable year as though it begins on the first day of the calendar month beginning nearest to the first day of such taxable year, or as though it ends with the last day of the calendar month ending nearest to the last day of such taxable year, as the case may be. See 26 U.S.C. section 441. The terms "tax year" and "taxable year" are generally used interchangeably for Missouri income tax purposes.