120X: Arizona Amended Corporation Income Tax Return (2025)
Arizona · Arizona DOR · Used for tax years 2025
Arizona Form 120X is used to amend a corporation’s Arizona income tax return for 2025. It reports originally reported or adjusted amounts, changes, and corrected amounts for income, tax, and credits, and calculates any payment due or overpayment.
Who files this form
Arizona Form 120X is for corporations amending an Arizona corporation income tax return. The form lists three reasons for filing:
- A finalized federal audit.
- An amended federal return.
- Arizona adjustments only.
This version is for calendar year 2025 or a fiscal year beginning in 2025. Use the Form 120X for the taxable year you are amending.
What you'll need
Have the information needed to show the originally reported or adjusted amounts, the changes, and the corrected amounts. This includes federal taxable income, Arizona adjustments, credits, and payment dates and amounts.
Depending on the changes, the form calls for:
- An explanation of changes in Schedule C.
- A computation schedule for an Arizona net operating loss carryover on line 14.
- Arizona Form 300 information for credit recapture and nonrefundable credits.
- The Schedule D worksheet if entering amounts on lines D6 or D8, and the Schedule E worksheet if entering amounts on lines E8 or E10.
- Arizona Schedule ACA for qualifying air carriers, or Schedule MSP for qualifying Multistate Service Providers.
- Supporting schedules for the applicable entries in Schedules F and G, including royalties, rental income, gains or losses from nonbusiness assets, and other income.
How to file
- Enter the corporation’s name, EIN, address, and tax year. Check the reason for amending and the applicable filing-method boxes.
- Show the originally reported or adjusted amounts in column (a), the amounts to add or subtract in column (b), and the corrected amounts in column (c).
- Complete the applicable schedules, including Schedule B for payments and Schedule C for the explanation of changes. Calculate the payment due or overpayment.
- Have the president, treasurer, or another principal officer sign the declaration. Enter the officer’s printed name, title, and date.
- Mail the return to:
Arizona Department of Revenue
PO Box 29079
Phoenix, AZ 85038-9079
Common mistakes
- Using the wrong year’s form. Do not use the 2025 Form 120X to amend a prior taxable year.
- Making a consolidated election on an amended return. The form warns that this election generally cannot be made on an amended return.
- Missing special apportionment schedules. Qualifying air carriers must use Schedule ACA. Qualifying Multistate Service Providers must include Schedule MSP.
- Completing unnecessary parts of Schedule A. If “Sales Factor Only” is checked, complete only Section A3, lines a through f.
- Skipping required worksheets. Complete the Schedule D worksheet for entries on D6 or D8 and the Schedule E worksheet for entries on E8 or E10.
- Writing in the revenue-use-only area. The form says not to mark that area.
Questions people ask
Can I use this form to amend an earlier tax year?
No. The form says not to use the 2025 Form 120X to amend a prior taxable year. Use the form for the year being amended.
What if the amended return includes a capital loss carryback?
Check box C and enter the last day of the tax year in which the capital loss originated.
Can an overpayment be applied to estimated tax?
Yes. Line 32 lets you apply part or all of the line 31 overpayment to 2026 estimated tax. Line 33 shows the remaining amount to be refunded.
Who must sign the return?
The declaration must be signed by the corporation’s president, treasurer, or another principal officer.
Which income lines do 100% Arizona corporations use?
Check box 5a and go from line 5 to line 13. All other corporations go to line 6.