What Form 1120-X Is For
Form 1120-X is the official IRS form used by corporations filing an amended return. It lets C corporations and certain corporations correct errors or omissions from their originally filed corporate returns. The form adjusts total income, deductions, and credits to produce a corrected taxable income. Every completed form must follow IRS requirements, business rules, and prescribed deadlines. Each corporation’s return must be signed by an authorized officer, accompanied by supporting documents, and submitted to the appropriate IRS address.
When You’d Use Form 1120-X
Corporations filing an amended return generally do so to correct errors on the original form or to report information discovered after the initial filing period. A corporation filed Form 1120-X when the original tax return was considered filed, and errors were later identified. Examples include adjusting estimated tax payments, correcting income taxes, or revising credit carryover amounts. A superseding return can be filed before the due date, while an amended return is submitted after the prescribed deadline. Timely filing ensures compliance with IRS guidelines and reduces potential penalties.
Key Rules or Details for Tax Year 2013
- Filing Deadlines: Corporations following a calendar year had until March 17, 2014, to file their 2013 corporation income tax return. Fiscal year filers followed the 15th day of the fourth month after the close of their tax year.
- Statute of Limitations: The three-year statute applies from the date the corporation’s return was originally filed or two years from the payment date. This period determines when a corporation may request a refund or a tentative refund.
- Electronic and Paper Filing: Certain corporations must use e-filing to comply with IRS regulations. Those unable to use XML form transmission can send paper forms to the appropriate IRS service center listed in the IRS address directory.
- Payment and Refund Rules: The corporation must pay immediately when an amended return increases taxes. The taxpayer may request a quick refund through approved waiver procedures. if overpaid
- Supporting Documentation: Corporations must attach other documents, such as amended schedules, supporting explanations, and the corrected form. Each line number and amended item must be clearly identified to ensure accuracy.
Browse more tax form instructions and filing guides in our Forms Hub.
Step-by-Step Filing Process (High Level)
Step 1: Gather Supporting Documents
Collect the original tax return, income schedules, subsidiary returns, and any other documents showing corrected information for prior years or tax years being amended.
Step 2: Complete the Amended Form
Enter figures for the corporation’s total income, deductions, and tax computation in three columns: originally filed, net change, and corrected amount. Each corrected form must list line numbers and include explanations in Part II.
Step 3: Attach Appropriate Forms and Explanations
Include all supporting explanations, main form attachments, and applicable changed schedules. Corporations filing must ensure that each XML document or paper form matches IRS guidelines.
Step 4: Calculate Tax Impact and Refund
Determine if the change produces additional taxes or a refund. Domestic corporations must pay any additional liability immediately or request a tentative refund if eligible under IRS rules.
Step 5: Provide Required Signatures
A signed signature document or practitioner’s PIN must be included. Authorized officers—such as the president or treasurer—must sign before the filing is complete.
Step 6: File at the Appropriate IRS Address
Send the amended return to the appropriate IRS service center. Corporations using e-filing must transmit through approved XML form software following IRS requirements and business rules.
Step 7: Retain Copies for Future Reference
Keep the completed form, supporting documents, and any approved waiver for at least three years from the filing period. This record helps corporations demonstrate compliance if audited.
Learn more about federal tax filing through our IRS Form Help Center.
Common Mistakes and How to Avoid Them
- Missing the Prescribed Deadline: Corporations must file within three years of the original tax return date to claim a refund.
- Incomplete Supporting Explanations: Each change requires an explanation referencing the exact line number on the corporation’s return. Clear detail helps the IRS process amended returns faster.
- Failing to Pay Additional Taxes: Corporations must pay immediately to avoid interest and penalties when corrected amounts increase taxable income.
- Incorrect IRS Address: Always verify the appropriate IRS address based on your corporation’s location and whether payment is included.
- Unsigned or Incorrectly Signed Forms: Required signatures are mandatory. The IRS will not process unsigned corporate returns, even if otherwise complete.
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 the corporation files Form 1120-X, the IRS reviews the amended form and supporting documentation. Processing time can vary based on complexity and whether additional taxes or a refund are due. The IRS may contact the taxpayer for clarification if it finds errors. A correctly filed amendment to a corporate income tax return helps ensure compliance and may prevent future potential penalties. Corporations should track the amendment and retain all supporting documents until complete processing.
FAQs
How long do corporations filing an amended return have to correct errors on a corporate income tax return?
Corporations generally have three years from the date the original tax return was considered filed, or two years from the payment date, to submit corrections.
Where should domestic corporations send an amended form or corporate income tax return?
Domestic corporations must use the appropriate IRS address for their region—the IRS service center directory lists where each amended return should be mailed or electronically filed.
Can a corporation file an amended return electronically using XML form submission?
Yes, certain corporations may e-file using XML documents. Those unable to e-file can submit paper forms with the required supporting documents.
What should be included with an amended return to ensure accuracy?
Each completed form must include supporting explanations, other documents, and a corrected form showing all amended items. This ensures IRS guidelines are properly followed.
Does the IRS provide a tentative or quick refund for overpaid income taxes?
Corporations can request a quick or tentative refund if the amended return shows overpayment, provided the claim is made within the prescribed deadline.
Who must provide the required signatures for corporate returns?
An authorized corporate officer must sign the completed form or use the practitioner’s PIN. Without required signatures, the filing is invalid and unfiled.
What happens if the amended return checkbox is not selected or the form is incomplete?
If the amended return checkbox is not selected, the IRS may treat the filing as incomplete. Corporations should ensure the checkbox is marked and all parts are filled out accurately.
For more resources on filing or understanding prior-year IRS forms, visit our guide on Business Income Tax Forms.
