Section 143.431 - Missouri taxable income and tax1. The Missouri taxable income of a corporation taxable under sections 143.011 to 143.996 shall be so much of its federal taxable income for the taxable year, with the modifications specified in subsections 2 to 4 of this section, as is derived from sources within Missouri as provided in section 143.451. The tax of a corporation shall be computed on its Missouri taxable income at the rates provided in section 143.071.2. There shall be added to or subtracted from federal taxable income the modifications to adjusted gross income provided in section 143.121, with the exception of subdivision (5) of subsection 2 of section 143.121, and the applicable modifications to itemized deductions provided in section 143.141. There shall be subtracted the federal income tax deduction provided in section 143.171. There shall be subtracted, to the extent included in federal taxable income, corporate dividends from sources within Missouri.3.(1) If an affiliated group of corporations files a consolidated income tax return for the taxable year for federal income tax purposes, then it may elect to file a Missouri consolidated income tax return. The federal consolidated taxable income of the electing affiliated group for the taxable year shall be its federal taxable income. All transactions between affiliated members of the affiliated group shall be eliminated on the Missouri consolidated income tax return.(2) So long as a federal consolidated income tax return is filed, an election made by an affiliated group of corporations to file a Missouri consolidated income tax return may be withdrawn or revoked only upon substantial change in the law or regulations adversely changing tax liability under this chapter, or with permission of the director of revenue upon the showing of good cause for such action. After such a withdrawal or revocation with respect to an affiliated group, it may not file a Missouri consolidated income tax return for five years thereafter, except with the approval of the director of revenue, and subject to such terms and conditions as he may prescribe.(3) No corporation which is part of an affiliated group of corporations filing a Missouri consolidated income tax return shall be required to file a separate Missouri corporate income tax return for the taxable year.(4) For each taxable year an affiliated group of corporations filing a federal consolidated income tax return does not file a Missouri consolidated income tax return, for purposes of computing the Missouri income tax, the federal taxable income of each member of the affiliated group shall be determined as if a separate federal income tax return had been filed by each such member.(5) The director of revenue may prescribe such regulations not inconsistent with the provisions of this chapter as he may deem necessary in order that the tax liability of any affiliated group of corporations making a Missouri consolidated income tax return, and of each corporation in the group, before, during, and after the period of affiliation, may be returned, determined, computed, assessed, collected, and adjusted, in such manner as clearly to reflect the Missouri taxable income derived from sources within this state and in order to prevent avoidance of such tax liability.4. If a net operating loss deduction is allowed for the taxable year, there shall be added to federal taxable income the amount of the net operating loss modification for each loss year as to which a portion of the net operating loss deduction is attributable. As used in this subsection, the following terms mean:(1)"Loss year", the taxable year in which there occurs a federal net operating loss that is carried back or carried forward in whole or in part to another taxable year;(2)"Net addition modification", for any taxable year, the amount by which the sum of all required additions to federal taxable income provided in this chapter, except for the net operating loss modification, exceeds the combined sum of the amount of all required subtractions from federal taxable income provided in this chapter;(3)"Net operating loss deduction", a net operating loss deduction allowed for federal income tax purposes under Section 172 of the Internal Revenue Code of 1986, as amended, or a net operating loss deduction allowed for Missouri income tax purposes under paragraph (d)* of subsection 2 of section 143.121, but not including any net operating loss deduction that is allowed for federal income tax purposes but disallowed for Missouri income tax purposes under paragraph (d)* of subsection 2 of section 143.121;(4)"Net operating loss modification", an amount equal to the lesser of the amount of the net operating loss deduction attributable to that loss year or the amount by which the total net operating loss in the loss year is less than the sum of: (a) The net addition modification for that loss year; and(b) The cumulative net operating loss deductions attributable to that loss year allowed for the taxable year and all prior taxable years.5. For all tax years ending on or after July 1, 2002, federal taxable income may be a positive or negative amount. Subsection 4 of this section shall be effective for all tax years with a net operating loss deduction attributable to a loss year ending on or after July 1, 2002, and the net operating loss modification shall only apply to loss years ending on or after July 1, 2002.Amended by 2018 Mo. Laws, SB 884,s A, eff. 8/28/2018.L. 1972 S.B. 549, A.L. 2004S.B. 1394 , A.L. 2007H.B. 444 , et al.