Mo. Rev. Stat. § 143.171 (2026)

  143.171.  Federal income tax deduction, amount, corporate and individual taxpayers. — 1.  For all tax years beginning on or after January 1, 1994, and ending on or before December 31, 2018, an individual taxpayer shall be allowed a deduction for his or her federal income tax liability under Chapter 1 of the Internal Revenue Code for the same taxable year for which the Missouri return is being filed, not to exceed five thousand dollars on a single taxpayer's return or ten thousand dollars on a combined return, after reduction for all credits thereon, except the credit for payments of federal estimated tax, the credit for the overpayment of any federal tax, and the credits allowed by the Internal Revenue Code by 26 U.S.C. Section 31, 26 U.S.C. Section 27, and 26 U.S.C. Section 34.

  2.  (1)  Notwithstanding any other provision of law to the contrary, for all tax years beginning on or after January 1, 2019, an individual taxpayer shall be allowed a deduction equal to a percentage of his or her federal income tax liability under Chapter 1 of the Internal Revenue Code for the same taxable year for which the Missouri return is being filed, not to exceed five thousand dollars on a single taxpayer's return or ten thousand dollars on a combined return, after reduction for all credits thereon, except the credit for payments of federal estimated tax, the credit for the overpayment of any federal tax, and the credits allowed by the Internal Revenue Code by 26 U.S.C. Section 31, 26 U.S.C. Section 27, and 26 U.S.C. Section 34.  The deduction percentage is determined according to the following table:

  (2)  Notwithstanding any provision of law to the contrary, the amount of any tax credits reducing a taxpayer's federal tax liability pursuant to Public Law 116-136 or 116-260, enacted by the 116th United States Congress, for the tax year beginning on or after January 1, 2020, and ending on or before December 31, 2020, and the amount of any tax credits reducing a taxpayer's federal tax liability under any other federal law that provides direct economic impact payments to taxpayers to mitigate financial challenges related to the COVID-19 pandemic shall not be considered in determining a taxpayer's federal tax liability for the purposes of subdivision (1) of this subsection.

  3.  For all tax years beginning on or after September 1, 1993, a corporate taxpayer shall be allowed a deduction for fifty percent of its federal income tax liability under Chapter 1 of the Internal Revenue Code for the same taxable year for which the Missouri return is being filed after reduction for all credits thereon, except the credit for payments of federal estimated tax, the credit for the overpayment of any federal tax, and the credits allowed by the Internal Revenue Code by 26 U.S.C. Section 31, 26 U.S.C. Section 27, and 26 U.S.C. Section 34.

  4.  If a federal income tax liability for a tax year prior to the applicability of sections 143.011 to 143.996 for which he was not previously entitled to a Missouri deduction is later paid or accrued, he may deduct the federal tax in the later year to the extent it would have been deductible if paid or accrued in the prior year.