Filing an amended return
Oregon doesn't have a specific amended return form for corporations. You’ll use the same form type you originally filed for the tax year you're amending and check the "amended" box. See the form instructions for additional information and requirements.
File your amended return separately from your current year’s return.
Don't amend to carry a net operating loss back. Oregon only allows corporations to carry net operating losses forward.
Prior tax liability
When preparing your amended return, on the estimated tax payments line, enter the net tax from the original return or as previously adjusted. Don't include penalty or interest payments.
Payment with your amended return
If paying additional tax with your amended return, you must include interest with your payment. Interest is calculated from the day after the due date of your original return up to the day we receive your full payment.
Pay all tax and interest due when you file your amended return, or within 30 days of receiving a billing notice from us, to avoid a 5 percent late payment penalty.
Don’t make your amended return payment by electronic funds transfer (EFT). You can pay using Revenue Online, or by check or money order. Make sure to write “Amended Payment” on your check or money order and include a completed Form OR-20-V with the “Amended” box checked.
An amended return may be filed as a protective claim to extend the statute of limitations for a refund request for a tax year while an issue is being litigated. Check the “Amended” box and write the words “Protective Claim for Refund” at the top. We’ll also accept a written letter in place of an amended return. Include the same information in the letter as is required on an amended return. We’ll hold your protective claim until you notify us the litigation is complete.
Note: If a deficiency is assessed against any taxpayer as a result of the retroactive adoption of federal law changes, we’ll cancel any resulting penalty or interest. If a taxpayer files an amended return showing a refund due based on the retroactive adoption of federal law changes, we won't pay interest on the refund.