Tax Administration Policy - Tax Return Due Dates
Portland City Code 7.02.510 A.2, Metro Code 7.05.170(a) and Multnomah County Code §§ 11.530 A. and 12.510(A) require tax returns to be filed by the fifteenth day of the fourth month following the end of the tax year.
Since the 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 tax returns 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 tax returns for the City of Portland, Metro, and Multnomah County business income taxes.
Since the C corporation business tax returns rely on the Oregon Form 20/Form 20-INC tax return filing, the due date for the business tax returns for C corporations are 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 late file 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.
03/17/2023 Thomas Lannom
Revised: March 2023