§ 143.811 RSMo — Interest on overpayment

1. Under regulations prescribed by the director of revenue, interest shall be allowed and paid at the rate determined by section 32.068 on any overpayment in respect of the tax imposed by sections 143.011 to 143.996 ; except that, where the overpayment resulted from the filing of an amendment of the tax by the taxpayer after the last day prescribed for the filing of the return, interest shall be allowed and paid at the rate of six percent per annum. With respect to the part of an overpayment attributable to a deposit made pursuant to subsection 2 of section 143.631 , interest shall be paid thereon at the rate in section 32.068 from the date of the deposit to the date of refund.

2. For purposes of this section:

(1) Any return filed before the last day prescribed for the filing thereof shall be considered as filed on such last day determined without regard to any extension of time granted the taxpayer;

(2) Any tax paid by the taxpayer before the last day prescribed for its payment, any income tax withheld from the taxpayer during any calendar year, and any amount paid by the taxpayer as estimated income tax for a tax year shall be deemed to have been paid by the taxpayer on the fifteenth day of the fourth month following the close of the taxpayer's tax year to which such amount constitutes a credit or payment.

3. For purposes of this section with respect to any withholding tax:

(1) If a return for any period ending with or within a calendar year is filed before April fifteenth of the succeeding calendar year, such return shall be considered filed April fifteenth of such succeeding calendar year; and

(2) If a tax with respect to remuneration paid during any period ending with or within a calendar year is paid before April fifteenth of the succeeding calendar year, such tax shall be considered paid on April fifteenth of such succeeding calendar year.

4. If any overpayment of tax imposed by sections 143.061 and 143.071 is refunded within four months after the last date prescribed (or permitted by extension of time) for filing the return of such tax or within four months after the return was filed, whichever is later, no interest shall be allowed under this section on overpayment.

5. If any overpayment of tax imposed by sections 143.011 and 143.041 is refunded within forty-five days after the date the return or claim is filed, no interest shall be allowed under this section on overpayment.

6. Any overpayment resulting from a carryback, including a net operating loss and a corporate capital loss, shall be deemed not to have been made prior to the close of the tax year in which the loss arises.

7. Any overpayment resulting from a carryback of a tax credit, including but not limited to the tax credits provided in sections 253.557 and 348.432 , shall be deemed not to have been made prior to the close of the tax year in which the tax credit was authorized.