(A) If any of the facts, figures, computations, or attachments required in an annual return filed by a taxpayer that has made the election allowed under section 171.80 of the Codified Ordinances and used to determine the tax due under sections 171.80 to 171.95 of the Codified Ordinances must be altered as the result of an adjustment to the taxpayer's federal income tax return, whether initiated by the taxpayer or the internal revenue service, and such alteration affects the taxpayer's tax liability under those sections, the taxpayer shall file an amended return with the tax commissioner in such form as the commissioner requires. The amended return shall be filed not later than sixty days after the adjustment is agreed upon or finally determined for federal income tax purposes or after any federal income tax deficiency or refund, or the abatement or credit resulting therefrom, has been assessed or paid, whichever occurs first. If a taxpayer intends to file an amended consolidated municipal income tax return, or to amend its type of return from a separate return to a consolidated return, based on the taxpayer's consolidated federal income tax return, the taxpayer shall notify the commissioner before filing the amended return.
(B) In the case of an underpayment, the amended return shall be accompanied by payment of any combined additional tax due together with any penalty and interest thereon. An amended return required by this section is a return subject to assessment under section 171.90 of the Codified Ordinances for the purpose of assessing any additional tax due under this section, together with any applicable penalty and interest. The amended return shall not reopen those facts, figures, computations, or attachments from a previously filed return no longer subject to assessment that are not affected, either directly or indirectly, by the adjustment to the taxpayer's federal tax return.
(C) In the case of an overpayment, an application for refund may be filed under this division within the sixty-day period prescribed for filing the amended return, even if that period extends beyond the period prescribed in section 171.91 of the Codified Ordinances, if the application otherwise conforms to the requirements of that section. An application filed under this division shall claim refund of overpayments resulting from alterations to only those facts, figures, computations, or attachments required in the taxpayer's annual return that are affected, either directly or indirectly, by the adjustment to the taxpayer's federal income tax return unless it is also filed within the time prescribed in section 171.91 of the Codified Ordinances. The application shall not reopen those facts, figures, computations, or attachments that are not affected, either directly or indirectly, by the adjustment to the taxpayer's federal income tax return. (Ord. 15-2018. Passed 3-5-18.)