What IRS Form 1120X (2015) Is For

IRS Form 1120X (2015) is the amended corporation income tax return that corporations use to correct errors on their original Form 1120 filed for the 2015 tax year. It allows corporations to fix mistakes, claim missed deductions, report additional income, or make certain elections after the original deadline (IRS Instructions for Form 1120X).

When You’d Use Form 1120X for 2015 (Late or Amended Filing)

You’d use Form 1120X for 2015 if you received IRS notices questioning your return, discovered errors that changed tax liability, or forgot to claim deductions or credits. Corporations also file it when uncovering unreported income or when current-year filings reveal prior-year mistakes. Refund claims must be made within the statute of limitations—three years from filing or two years from payment.

Key Rules Specific to 2015

• Failure-to-file penalty: 5% of unpaid tax per month, up to 25%.
  
  
• Minimum late filing penalty: $135 for returns over 60 days late.
  
  
• Failure-to-pay penalty: 0.5% per month of unpaid tax.
  
  
• Corporate tax rates: graduated structure, 15% to 35%.
  
  
• E-filing mandatory for corporations with $10 million+ assets and 250+ returns.
  
  
• Affordable Care Act employer reporting rules applied beginning 2015.

Step-by-Step (High Level)

• Gather transcripts: Collect your original 2015 Form 1120 and IRS transcripts.
• Complete Form 1120X: Fill in the three-column format with explanations in Part II.
• Attach supporting documents: Include schedules, forms, or statements supporting your changes.
• Submit your return: Mail to the IRS service center where the original return was filed.
• Keep copies: Retain all submissions, as amended returns often take 3–4 months to process.

Common Mistakes and How to Avoid Them

• Incomplete explanations: Provide detailed justifications in Part II for every change.
  
  
• Wrong filing address: Send the return to the same center that processed the original.
  
  
• Missing documentation: Always attach schedules and forms supporting your changes.
  
  
• Math errors: Verify corrected amounts in Column C match updated tax computations.
  
  
• Filing too early: Wait until your original return is fully processed.
  
  
• Ignoring carryback rules: Attach returns for loss or credit carrybacks with proper statements.
  
  

What Happens After You File

Processing takes about 3–4 months. The IRS may issue acknowledgment notices, request documentation, or adjust your return. If additional tax is owed, you’ll receive a bill with interest from the original due date. Refunds are issued as checks or direct deposits, with interest where applicable. Disputed adjustments provide appeal rights, including Appeals Office review or Tax Court petitions.

FAQs

How long do I have to file Form 1120X for 2015?

Corporations must file Form 1120X within three years of the original filing date or two years from the date tax was paid, whichever is later. For 2015 returns filed by March 15, 2016, the general deadline was March 15, 2019. Filing after this period typically prevents claiming refunds.

Will I face penalties for filing an amended return?

There is no penalty for filing the amendment itself. However, if the amendment shows additional tax due, failure-to-pay penalties and interest accrue from the original due date until payment is made. Filing promptly and paying outstanding amounts quickly reduces both penalty and interest charges.

Can I get my tax account transcript to help prepare the amendment?

Yes, transcripts are available from the IRS by calling 1-800-829-4933, using IRS.gov, or submitting Form 4506-T. Account transcripts show what the IRS processed originally, while record transcripts include line-by-line details. Reviewing transcripts ensures accuracy when preparing corrections on Form 1120X.

What if my amended return shows I overpaid and deserve a refund?

File Form 1120X as soon as possible because refund claims are time-limited. The IRS will verify your changes and issue a refund check or direct deposit if approved. Interest is typically added, calculated from the date of original filing to the refund issuance date.

Do I need to amend my state return too?

Yes, most states require amended returns when the federal corporate return is corrected. Since each state has unique rules and deadlines, check your state’s tax agency for conformity provisions and filing requirements. Failure to file amended state returns can lead to penalties or mismatched assessments.

Can I file Form 1120X electronically?

No, Form 1120X cannot be e-filed. It must be submitted by mail to the IRS service center where the original return was filed. Corporations should track mailing dates and use certified mail or delivery confirmation to prove timely submission of their amendment.

What if I filed multiple years incorrectly?

You must file a separate Form 1120X for each year requiring correction. Each year has its own statute of limitations and must be amended independently. Be sure to provide supporting documents and explanations for each amended year to avoid processing delays or rejection by the IRS.

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