What Form 1120-X Is For
Form 1120-X is the official Internal Revenue Service amended form that certain corporations use to correct errors on a previously filed corporate tax return. Corporations file this document when they need to report adjusted taxable income, claim additional credits, or pay additional taxes after processing their original tax return. It ensures accuracy by allowing corporations to replace incorrect information with the corrected amount and provide supporting documentation to explain each change.
When You’d Use Form 1120-X
Corporations file Form 1120-X when their original return requires adjustments after the prescribed deadline. This situation may arise when a corporation files its original form and later discovers that it reported total income, deductions, or credits incorrectly; this amended return also applies if the business name or employer identification number was entered inaccurately. Corporations must use this form only after filing the original return and submitting all supporting documents showing the correct information.
Key Rules or Details for 2011 Tax Year
- Filing deadline: Corporations must file amended returns within three years of filing the original tax return or within two years of tax payment, whichever is later.
- Filing format: In the 2011 tax year, e-filing for Form 1120-X was unavailable. Corporations must submit original tax returns and supporting documents to the appropriate IRS Service Center.
- Authorized signature: For the IRS to accept the completed form, it must include the signature of a corporate officer.
- Supporting schedules: Corporations must attach all schedules and forms that support each adjustment made, including explanations for each affected line number and corrected figure.
- Accounting consistency: When adjusting total income, deductions, or taxable income, corporations must review every related schedule to ensure accuracy across the corporate return.
- Statutory elections: Certain elections missed on the original return may be made on an amended form, provided the IRS allows late elections under specific regulations.
- Recordkeeping: Corporations should save copies of all forms and documents for audit purposes and maintain accurate records showing each adjustment for affected tax years.
Browse more tax form instructions and filing guides in our Forms Hub.
Step-by-Step (High Level)
Step 1: Gather Your Documents
Corporations should collect the original tax return, all schedules, and records supporting the corrections. This includes prior year adjustments, supporting documentation, and any IRS correspondence that affects taxable income or total assets.
Step 2: Complete the Form Header
Enter the corporation’s legal business name, employer identification number, address, and applicable tax year. Indicate which IRS Service Center received the original filing to ensure correct processing.
Step 3: Fill Out Part I
Corporations must use the three-column layout: the original return figures, the amount of change, and the corrected amount. Each line must equal the adjustment shown, ensuring total income and tax computation consistency.
Step 4: Write an Explanation in Part II
Part II is critical. Corporations must clearly explain each correction, specifying the line numbers affected and the reason for the change. The IRS requires adequate detail to process the amended return.
Step 5: Attach Supporting Documents
Corporations must attach revised schedules, statements, or other documents supporting income adjustments, deductions, or credits. Each attached page must clearly reference the corporate return's relevant section or line number.
Step 6: Sign and Date
A corporate officer must sign and date the completed form. The IRS will not process any unsigned or incomplete returns, so authorized personnel must confirm that all details are correct.
Step 7: Mail and Keep Copies
Corporations must mail the amended return to the same IRS Service Center where the original form was filed. Always keep a full copy of the completed form, explanation pages, and support for future reference.
Learn more about federal tax filing through our IRS Form Help Center.
Common Mistakes and How to Avoid Them
- Filing too early: A corporation cannot file an amended return before the IRS has processed the original return. Waiting ensures that all adjustments are properly reviewed.
- Insufficient explanation: A vague explanation in Part II causes delays. Each amendment should include whether the IRS processed the original return and the reason for the adjustment.
- Omitting documentation: Corporations must attach all supporting documentation, such as adjusted schedules or statements, to verify the corrections. Missing attachments may cause the IRS to reject the filing.
- Mathematical errors: Column totals must equal the original figures plus or minus any adjustments. Review the corrected amounts carefully before mailing the completed form.
- Incorrect form usage: Form 1120-X applies only to corporate returns. As indicated on the IRS website, certain corporations must use different forms to request a tentative refund or apply carrybacks.
- Unsigned form: The amended form must include an officer’s signature. The IRS will return unsigned forms, delaying refund processing or adjustments.
Learn more about how to avoid business tax problems in our guide on How to File and Avoid Penalties.
What Happens After You File
After filing Form 1120-X, the IRS begins processing the amendment, which can take up to 16 weeks. The IRS reviews all attached explanations, ensures the correct math, and verifies supporting documentation. The amount is processed separately from the original filing if the corporation claims a refund. Corporations owing additional taxes should include payment with the amended return to avoid interest. Corporations must also file amended state returns to maintain compliance across all tax years if corrections affect state filings.
FAQs
Can I e-file Form 1120-X for my 2011 corporation income tax return?
For the 2011 tax year, corporations could not e-file amended returns. The IRS requires paper filing, including all supporting documentation and explanations, to be submitted to the proper Service Center.
What if my amended return changes my total assets or taxable income?
Corporations must update every related schedule when changes affect total assets, income, or deductions. Correcting errors on one line may alter dependent calculations elsewhere on the corporate return.
How long do I have to file an amended return under Form 1120X?
Corporations generally have three years from the original tax return filing or two years after taxes were paid. The later date applies to refund claims.
How do I correct errors in Part II of Form 1120-X?
Corporations must explain the original tax return amount and the corrected figure. The explanation should describe how the adjustment affects taxable income.
Can I use PDF editing tools to complete my Form 1120-X?
Corporations may use secure PDF editing software to fill out, save, and print the amended form. The completed document must still be mailed with proper signatures and attachments.
Should all corporate returns be amended if one year is corrected?
Only the affected corporate return must be amended. However, adjustments in one year may affect future or prior tax years, requiring review of additional corporate returns to ensure accuracy.
Can I print the corrected form directly from the IRS website?
Corporations can download and print Form 1120-X from the IRS website. Always use the latest PDF version to ensure compliance with applicable instructions.
For more resources on filing or understanding prior-year IRS forms, visit our guide on Business Income Tax Forms.
