What Form 1120-X Is For
Form 1120-X allows domestic corporations to amend a previously filed corporate tax return when they need to correct errors or update financial information. This amended form helps corporations fix incorrect income amounts, deductions, credits, or elections mistakenly reported on the original form. The IRS requires a completed form with all supporting documents and explanations for each amended item to ensure accuracy in your corporate return. Following proper IRS regulations prevents potential penalties or delays during review.
When You’d Use Form 1120-X
Only after filing and having the IRS consider the original return as filed can corporations use Form 1120-X. You should file this amended return if you discover calculation mistakes, missed deductions, or new information that changes your taxable income. Corporations cannot use this form to supersede returns filed before the prescribed deadline. Instead, Form 1120-X applies only when amending an original tax return after the filing period has closed. Paper and e-filing are available, depending on IRS requirements for that tax year.
Key Rules or Details for 2012
- Three-Year Limitation Rule: Corporations must file the amended return within three years after the original tax return’s due date or within two years of paying additional taxes. Filing after these deadlines invalidates any claim for refund.
- Proper IRS Address: Always mail the paper filing to the appropriate IRS address or IRS service center where the original return was submitted. The IRS website lists all correct addresses based on your corporation’s location.
- Supporting Documentation: Attach all supporting documents explaining each correction, including schedules and statements. Corporations must include line numbers, corrected amounts, and supporting explanations for every amended item.
- Approved Waiver and Tentative Refunds: Corporations requesting a tentative refund or using an approved waiver must follow IRS guidelines and submit appropriate forms within the permitted tax years.
- Electronic and XML Filing: Certain corporations may e-file amended returns through an XML form submission that complies with IRS requirements for data accuracy.
- Credit Carryover or Net Operating Loss: If the corporation filed for a credit carryover or net operating loss adjustment, ensure the tax computation reflects these corrections clearly in Part II of the completed form.
- Required Signatures: The amended form must include the required signatures from an authorized corporate officer, a preparer’s practitioner’s PIN if applicable, and a signed signature document when e-filing.
- PDF Editing for Recordkeeping: When preparing a paper filing, corporations may use IRS-approved PDF editing software to ensure clear and legible entries before submission.
Browse more tax form instructions and filing guides in our Forms Hub.
Step-by-Step (High Level)
Step 1: Wait for the Original Return to Process
The IRS must process and consider corporations' original Form 1120 as filed. Filing an amended return before confirmation can lead to processing errors.
Step 2: Gather Prior Returns and Supporting Documentation
Collect the original form, subsidiary returns, supporting documentation, and all corrected schedules. Include receipts, workpapers, or other proof needed to substantiate your changes.
Step 3: Complete the Main Form Sections
Enter the corporation’s business name, employer identification number, and tax year. In Part I, report total income, deductions, and corrected amounts. Ensure that column totals match correctly to prevent computation errors.
Step 4: Explain Changes in Part II
List each line number, amended item, and reason for the correction. Provide supporting explanations following IRS regulations. Detailed justifications help the IRS confirm that the amended return is accurate and complete.
Step 5: Attach Corrected and Supporting Forms
Attach each corrected form, such as revised schedules, depreciation records, or credit forms. Write “Copy Only—Do Not Process” at the top of these attachments to distinguish them from the main form.
Step 6: Sign and File with the IRS
An authorized officer must sign the completed form and include the required signatures. Mail the paper filing to the appropriate IRS address or submit the XML document electronically if e-filing is allowed for your corporation’s tax year.
Learn more about federal tax filing through our IRS Form Help Center.
Common Mistakes and How to Avoid Them
- Omitting Supporting Documents: Corporations must attach all supporting documentation when submitting amended returns to ensure the IRS has the correct information to verify corrections accurately.
- Incorrect Column Totals: Verify that the tax computation in each column adds up correctly so the corrected amount equals the original plus or minus the amendment value.
- Incomplete Explanations: Provide full supporting explanations for each amended item in Part II so the IRS can clearly follow your reasoning and adjustments.
- Filing Before the Original Return Is Processed: Wait until the IRS files the corporation’s original return to prevent mismatches in processing systems.
- Missing Signatures or Practitioner’s PIN: Always include the authorized corporate officer’s signature and any practitioner’s PIN when e-filing to meet IRS requirements.
- Sending to the Wrong Address: To avoid delayed or rejected filings, confirm the appropriate IRS address or IRS service center on the IRS website.
- Ignoring the Amended Return Checkbox: Make sure the amended return checkbox is selected on the form so the IRS can properly classify your filing as an amended return.
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 submitting Form 1120-X, corporations should allow up to four months for processing. The IRS will review each amended item and verify all supporting explanations. If additional taxes are owed, interest will accrue from the original due date until payment is received. If you qualify for a refund, it will be issued once the IRS approves the corrected form. Always retain a copy of the amended return, supporting documents, and correspondence for future reference in case of audits or clarifications.
FAQs
Can I e-file Form 1120-X for my 2012 corporate tax return?
The 2012 Form 1120-X required paper filing only. Under IRS requirements, electronic filing was not yet supported for corporate returns from that year.
What if the corporation filed late and now needs an amended return?
If the corporation filed after the prescribed deadline, it can still file an amended return to correct errors. However, refund eligibility depends on statute limits.
How does the IRS handle correcting errors on a 2012 corporate return?
The IRS reviews the amended form, supporting documentation, and calculations when correcting errors. Corporations should ensure accuracy to avoid potential penalties.
Can corporations amend subsidiary returns using Form 1120-X?
Corporations can amend subsidiary returns under consolidated corporate returns using Form 1120-X, provided they properly attach all supporting forms and corrected schedules.
Where do corporations send a paper filing for Form 1120-X?
Corporations should follow official business rules and mail the completed form to the appropriate IRS address or service center listed on the IRS website.
What are the IRS requirements for supporting documentation with amended returns?
Each amended return must include supporting explanations, schedules, and forms detailing corrected amounts. This ensures compliance with IRS regulations and reduces review time.
Can I use PDF editing software to prepare my Form 1120-X?
Yes, IRS guidelines allow corporations to use PDF editing tools to prepare clear, legible forms before paper submission, provided the content matches the XML form layout exactly.
For more resources on filing or understanding prior-year IRS forms, visit our guide on Business Income Tax Forms.
