120X: Arizona Amended Corporation Income Tax Return (2024)
Arizona · Arizona DOR · Used for tax years 2024
Arizona Form 120X is the amended corporation income tax return for tax year 2024. It reports changes to previously reported income, adjustments, tax credits, and payments, and calculates any additional amount 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.
Use the 2024 version for calendar year 2024 or a fiscal year beginning in 2024. Do not use it to amend a prior taxable year.
What you'll need
Have the following information ready to complete the form:
- The amounts originally reported or previously adjusted, the changes, and the corrected amounts.
- Your federal return, including federal taxable income and the business activity code from federal Form 1120.
- Payment dates and amounts for the payment with the original return and payments made after filing, for Schedule B.
- An explanation of changes for Schedule C.
Depending on your return, you may also need:
- A computation schedule for an Arizona net operating loss carryover claimed on line 14. The form requires this schedule to be included.
- Arizona Form 300 for tax credit recapture and nonrefundable credit amounts.
- Apportionment information for a multistate corporation. Qualifying air carriers must use Schedule ACA, and qualifying Multistate Service Providers must include Schedule MSP.
- Federal Form 1120 or payroll reports for the payroll factor if using standard apportionment.
How to file
- Enter the corporation's identifying information, tax year, and reason for amending.
- Enter the original 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 declaration signed and dated by the president, treasurer, or another principal officer. Enter the officer's title and printed name.
Mail the return to:
Arizona Department of Revenue
PO Box 29079
Phoenix, AZ 85038-9079
Common mistakes
- Using the wrong year's form. The form warns not to use the 2024 Form 120X to amend a prior taxable year. Use the form for the year being amended.
- Marking the revenue-use-only area. The form says not to mark in that area.
- Missing special apportionment schedules. Qualifying air carriers must use Schedule ACA. Qualifying Multistate Service Providers must include Schedule MSP.
- Completing the wrong apportionment sections. If the “Sales Factor Only” box on page 1, line D, is checked, complete only Schedule A, Section A3, lines a through f.
- Assuming a consolidated election can be made on an amended return. The form notes that this election generally cannot be made on an amended return.
Questions people ask
How is the tax on line 16 calculated?
Enter 4.9 percent of Arizona taxable income on line 15 or $50, whichever is greater.
Can an overpayment be applied to next year's estimated tax?
Yes. On the 2024 form, line 32 lets you apply part or all of the line 31 overpayment to 2025 estimated tax. Line 33 shows the amount to be refunded after subtracting line 32 from line 31.
What should a corporation operating entirely in Arizona do after line 5?
The form directs 100% Arizona corporations to check box 5a and go to line 13. All others go to line 6.
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.