Maintain Corporate Tax

When is my corporate income tax return due?

Your Missouri return is due the 15th day of the 4th month following the year end.

Common Filing Mistakes

  • The form was not signed.
  • A copy of the extension was not included.
  • A copy of the federal return and all supporting schedules was not included.
  • The Missouri tax ID number was not included.
  • A copy of the balance sheet and all supporting schedules was not attached.
  • Non-business income was claimed and a detailed explanation of the non-business income was not attached.
  • Wholly passive investment income was claimed and a detailed explanation was not attached.

What is the tax rate for Missouri corporation income tax?

For tax years beginning on or after September 1, 1993, the tax rate is 4 percent. For tax years before September 1, 1993, the tax rate is five percent, except for tax years 1990 and 1991 when the rate was graduated.

How is the graduated corporate income tax calculated?

For all tax years beginning on or after January 1, 1990, but not after December 31, 1991, use the income rates below:

Missouri Taxable Income on Line 10 of Form MO-1120X:

Over But Not Over Tax Rate On Excess Over
$0 $100,000 5% $0
$100,000 $335,000 $5,000 + 6% $100,000
$335,000   $19,100 + 6.5% $335,000

How do I file an amended return?

For tax years beginning on or after January 1, 1993, the same form is used to file an amended return that was used to file the original return. Check the box to indicate that it is an amended return. For tax years prior to 1993, the Form MO-1120X is used.

Extension of Time to File and Pay

If a corporation has been granted an extension of time to file its federal income tax return, the time for filing the Missouri Corporation Tax Return is automatically extended for the same period of time. A copy of the Federal Extension, Form 7004, must be attached to the Form MO-1120 when filed. An extension of time to file a Corporation Tax Return does not extend the time for payment of the tax.