What IRS Form 1120 (2015) Is For

Form 1120 is the U.S. Corporation Income Tax Return that domestic C corporations use to report their annual income, gains, losses, deductions, and credits (IRS Instructions for Form 1120 (2015)). The form determines the corporation’s federal income tax liability. All domestic corporations must file Form 1120 unless they are exempt, dissolved, or eligible for a different form (such as Form 1120-S for S corporations). Even corporations with no income must generally file.

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

You’d need to file a late 2015 Form 1120 if the corporation never filed by the original due date (March 15, 2016, for calendar-year filers) and has since received IRS notices demanding the return, or if you discovered unreported income or incorrect deductions. Amended returns are filed using Form 1120X when you need to fix partner or corporate income details, deductions, or credits. For refund claims, the statute of limitations expired March 15, 2019, so refunds can no longer be claimed unless exceptions apply (IRS Instructions for Form 1120X). Filing late still establishes compliance and may limit additional penalties.

Key Rules Specific to 2015

• Filing deadline: Returns were due the 15th day of the 3rd month after year-end (March 15, 2016, for calendar-year corporations). This changed to the 4th month (April 15) for tax years beginning after 2015.
  
  
• NOL carrybacks: Net operating losses could be carried back two years and forward 20 years (IRS Publication 536 (2015)). This is more generous than current rules, which generally prohibit carrybacks.
  
  
• Schedules required:
  
  
  
  • Corporations with assets ≥ $10 million had to file Schedule M-3 instead of M-1.
    
    
  • Corporations with assets < $250,000 and receipts < $250,000 could skip Schedules L, M-1, and M-2.
    
    
• Penalty structure: Late filing penalties were 5% of unpaid tax per month (up to 25%), with a minimum penalty of $135 if more than 60 days late.
  
  

Step-by-Step (High Level)

1. Gather transcripts and records: Request account transcripts from the IRS for 2015 and surrounding years to confirm filing status, payments, or penalties.
   
   
2. Use the correct form year: Download the official 2015 Form 1120 from IRS.gov prior-year forms. Don’t use current-year versions.
   
   
3. Complete the return: Include all required schedules, such as Schedule M-1 or M-3, Schedule M-2, and supporting statements for deductions or elections.
   
   
4. Mail or e-file: Paper filing is required for most very late returns, though some e-filing providers may still support prior-year submissions. Send to the service center listed in the 2015 instructions.
   
   
5. Keep records: Maintain copies of the return, schedules, and proof of mailing or electronic confirmation for at least 3 years, longer if NOL carryovers are involved.
   
   

Common Mistakes and How to Avoid Them

• Wrong form year: Always use the 2015 version, as line items and requirements differ significantly from later forms.
  
  
• Incorrect due date calculation: Remember that 2015 filings were due in the 3rd month after year-end, not the 4th.
  
  
• Missing schedules: Large corporations must file Schedule M-3; mid-sized corporations must complete Schedules M-1 and M-2.
  
  
• NOL errors: Misreporting carrybacks or failing to elect out of carryback periods can create IRS mismatches.
  
  
• Unsigned returns: Returns without an officer’s signature are invalid and treated as unfiled.
  
  
• Penalty miscalculations: Don’t underestimate penalties—late filing is 5% per month of unpaid tax, while late payment adds 0.5% per month, both capped at 25%.
  
  

What Happens After You File

• Processing time: Typically 8–12 weeks for paper returns; longer if manual review is needed.
  
  
• IRS notices: You may receive CP notices confirming receipt, adjusting figures, or assessing penalties.
  
  
• Payments: Interest and penalties continue accruing until tax is fully paid. Installment agreements can be requested using Form 9465 if the balance is $50,000 or less.
  
  
• Appeal rights: If you disagree with IRS changes, you generally have 30 days to respond or protest. Cases may be escalated to the IRS Office of Appeals.
  
  
• No refunds: Refunds are not available for late 2015 returns filed after March 15, 2019, but filing remains important for compliance.
  
  

FAQs

Can I still get a refund from a 2015 Form 1120 filed now?

No. The three-year refund statute expired on March 15, 2019. Refund claims are barred unless rare exceptions apply (IRS Instructions for Form 1120X).

What penalties apply if I file my 2015 Form 1120 late?

The penalty is 5% of unpaid tax per month (up to 25%), with an additional 0.5% per month for late payment. If more than 60 days late, a minimum penalty of $135 applies, even if no tax is due.

Do I have to file if my corporation had no income?

Yes. Domestic corporations must file Form 1120 each year unless they are formally dissolved or qualify for exemption (IRS Instructions for Form 1120 (2015)).

Should I also amend state corporate returns?

Most states require amended state returns when you amend federal filings. Check your state’s specific rules and deadlines, as statutes of limitations vary.

Can I e-file a 2015 return?

Generally no. Most providers no longer support e-filing for 2015, so late returns should be filed by paper. Always send by certified mail to verify submission.

How do I get IRS transcripts for 2015?

Request them at IRS.gov using the Get Transcript tool, by calling 1-800-908-9946, or by submitting Form 4506-T. Transcripts confirm whether the IRS already recorded a filing.

What if I discover errors after filing?

Use Form 1120X to amend the return. However, amended returns cannot generate refunds at this point, since the refund statute has expired.

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