Starting with the 2016 tax year, the extended due date of the Oregon Form 20 (Corporate Excise Tax Return) and Form 20-INC (Corporate Income Tax Return) is one month later than the extended due date of the Combined Tax Return. For calendar year 2016 taxpayers, the Oregon extended due date of November 15 is one month after the City/County (Combined Tax Return) October 15 extended due date. This is problematic as the City/County return is based on the figures reported on the Oregon return.

Typically, the Oregon return is finalized at the same time as the federal return (which is due one month earlier), so this discrepancy should not impact many taxpayers. If you are not able to finalize your Oregon return by the extended due date of the Combined Tax Return, you will be granted a grace period for penalty assessments as long as your Combined Tax Return is filed by the Oregon extended due date. If you are assessed a penalty under these circumstances, it will be waived upon request. However, there will be no waiver or reduction of interest due that results from the discrepancy.