OR-37: Form OR-37, Underpayment of Oregon Corporation Estimated Tax (2025)
Oregon · Oregon DOR · Used for tax years 2025
Form OR-37 calculates underpayment of Oregon corporation estimated tax for 2025. It uses required quarterly installments and estimated tax paid or credited to figure overpayments or underpayments, with installment calculations based on current-year tax, prior-year tax, annualized
Who files this form
Include 2025 Form OR-37 with your Oregon corporation return if you owe interest on underpaid estimated tax or meet an exception. Check the “Form OR-37” box on your return.
What you'll need
Have these returns and records available to complete the form:
- Your current-year Oregon corporation return, Form OR-20, OR-20-INC, OR-20-INS, or OR-20-S, for your net excise or income tax.
- Your prior-year net excise or income tax amount.
- Your corporation’s legal name as shown on your Oregon return and federal employer identification number (FEIN).
- Records of estimated tax paid or credited for each quarter, payment dates, and applicable due dates.
- If using the annualized income worksheet, income for each selected period, net losses carried forward from prior tax years, and credits the corporation is entitled to for those months.
How to file
Include Form OR-37 with your corporation return if you owe interest or meet an exception. Check the “Form OR-37” box on the return.
Enter the total interest from line 21 on your return’s “interest on underpayment of estimated tax” line.
The form does not provide a mailing address or e-file instructions.
Common mistakes
- Use UPPERCASE letters and blue or black ink.
- Print the form at actual size (100%).
- Do not submit photocopies or use staples.
- High-income taxpayers may use exception 2 only for the first installment. The form directs these taxpayers to the instructions.
- Remember to include the form with your corporation return if you owe interest or meet an exception, and check the “Form OR-37” box.
Questions people ask
What does Form OR-37 calculate?
It calculates required estimated tax installments, quarterly underpayments, and interest on those underpayments for Oregon corporations.
Which exceptions are listed on the form?
The form lists four: current-year net tax, prior-year net tax, annualized income, and recurring seasonal income. It notes that high-income taxpayers may use the prior-year tax exception only for the first installment.
Where do I enter the total interest on my return?
Add the quarterly interest amounts on lines 20a through 20d and enter the total on line 21. Transfer that amount to the “interest on underpayment of estimated tax” line on your return.
What ending date is used to count days for underpayment interest?
For quarters 1 through 3, the form uses the earlier of the date the installment was paid or the next installment’s due date. For quarter 4, it uses the earlier of the date the installment was paid or the return’s due date.