Business Tax Policy: Combined Tax Return Due Dates
Portland City Code Section 7.02.510 A.2 and Multnomah County Code § 12.510(A) require Combined Tax Returns to be filed by the fifteenth day of the fourth month following the end of the tax year.
Since the Combined Tax Returns rely on information reported on federal and/or Oregon tax returns, it is the policy of the Revenue Division to change the due date for the Combined Tax Return when there is a change to the federal or State of Oregon due dates.
For tax years beginning on or after January 1, 2016, the Internal Revenue Service changed the due date of Form 1120 (C-corporation Returns) to the fifteenth day of the fourth month following the close of the tax year for most C-corporation taxfilers. The State of Oregon due date for Form 20 (Corporate Excise Tax Return) and Form 20-INC (Corporate Income Tax Return) is due the fifteenth day of the month following the IRS due date, which is one month later than the due date for the Combined Tax Return.
Since the C-corporation Combined Tax Return relies on the Oregon Form 20/Form 20-INC tax return filing, the due date for the Combined Tax Return for C-corporations is granted an automatic one-month extension to match the due date for the Oregon corporate return filing. This also applies to the extended filing due date.
If a C-corporation is assessed a penalty under these circumstances, it will be waived upon request. However, the due date for paying the C-corporation taxes has not been extended and are still due on the fifteenth day of the fourth month following the end of the tax year. No waiver or reduction of interest will be allowed for late payment of the tax liability.
9/29/2020 Thomas Lannom
Date Director, Revenue Division