What IRS Form 1120 (2018) Is For

Form 1120 is the U.S. Corporation Income Tax Return used by C corporations to report income, deductions, credits, gains, and losses for federal tax purposes (IRS Instructions for Form 1120 (2018)). All domestic corporations, including those in bankruptcy, must file unless they qualify for a special return (such as Form 1120-S) or are exempt under section 501.

When You’d Use Form 1120 for 2018 (Late or Amended Filing)

A late 2018 Form 1120 is filed if the corporation received an IRS notice for an unfiled return, discovered unreported income, or needs to claim a refund. Refund claims must generally be filed within three years of the original due date or two years of tax payment. For calendar-year filers, the refund statute expired April 15, 2022.

Key Rules Specific to 2018

• Flat tax rate: The Tax Cuts and Jobs Act introduced a flat 21% corporate tax rate, replacing prior graduated brackets.
  
  
• AMT repeal: The corporate alternative minimum tax (AMT) was eliminated beginning in 2018.
  
  
• New provisions: Corporations had to comply with new rules, including GILTI (section 951A), FDII (section 250), and section 245A foreign dividend deductions.
  
  
• NOLs: Net Operating Losses generated in 2018 can no longer be carried back but can be carried forward indefinitely, limited to 80% of taxable income.
  
  
• Repealed deduction: The domestic production activities deduction (DPAD) was eliminated.
  
  
• Business interest limitation: Section 163(j) introduced new limits on interest expense deductions.
  
  

Step-by-Step (High Level)

1. Gather IRS transcripts: Request account transcripts online or by calling 1-800-908-9946.
   
   
2. Use the 2018 version of Form 1120: Complete the correct-year form and instructions.
   
   
3. Attach required schedules: Include Schedules L, M-1, and M-2 unless the small corporation exception applies; add Schedule D, Schedule N, and others as needed.
   
   
4. Apply new rules: Use Form 8992 for GILTI, Form 8993 for FDII, and Form 8990 for business interest limitations.
   
   
5. Check penalties: Calculate underpayment penalties using Form 2220 if estimated tax deposits were insufficient.
   
   
6. Submit return: File electronically if available or mail to the correct service center.
   
   
7. Maintain records: Keep all supporting documentation and filed returns for at least three years.
   
   

Common Mistakes and How to Avoid Them

• Using outdated tax rates: Apply the flat 21% corporate tax rate, not pre-2018 graduated brackets.
  
  
• NOL errors: 2018 NOLs cannot be carried back and must follow the 80% taxable income limitation when carried forward.
  
  
• Omitted schedules: Corporations often forget to file Schedule M-1 or M-2 when required.
  
  
• Fiscal year deadline errors: June 30 year-end filers had a different due date (September 15, 2019).
  
  
• Missing new forms: Don’t overlook Form 8992, 8993, or 8990 for international or interest expense reporting.
  
  
• Incomplete deposits: Use EFTPS for all tax deposits; failure to deposit properly can lead to additional penalties.
  
  

What Happens After You File

Processing of 2018 corporate returns typically takes 6–8 weeks for paper filings, with amended returns taking longer. Corporations receive IRS notices confirming acceptance, reporting balances due, or requesting more information. If tax is owed, penalties and interest continue to accrue until payment is made. Payment plans may be requested using Form 9465, though interest accrues on balances.

FAQs

Can I still get a refund for 2018?

No, the three-year refund statute expired for most corporations on April 15, 2022. Refunds are no longer available unless exceptions apply. However, filing remains important to prevent IRS enforcement and penalties. Even if refunds are barred, corporations must file to properly report income and stop further penalties and interest.

What’s the penalty for filing my 2018 return now?

The penalty is 5% of unpaid tax per month up to a maximum of 25%, plus interest from the original due date. For returns more than 60 days late, a minimum $210 penalty applies. Penalties and interest continue to accrue until full payment, making filing sooner essential to minimize liability.

Do I need tax transcripts before filing?

Yes, obtaining IRS account transcripts is highly recommended. These records show previously reported payments, third-party information returns, and IRS adjustments. Reviewing transcripts helps prevent duplicate reporting and ensures that late or amended returns are accurate. Request transcripts online, by phone, or using Form 4506-T.

Should I also amend my state return?

Yes, most states require amended corporate returns if you file a federal amendment. State requirements vary, but in most cases, federal changes that affect income, credits, or losses must be reported to state tax agencies. Check with your state tax authority for exact deadlines and forms.

Can I e-file a late 2018 return?

E-filing for late prior-year returns is often restricted. Some providers still allow electronic filing of 2018 returns, but many require paper filing. Corporations should verify availability with tax software providers or plan to mail the return directly to the appropriate IRS service center for processing.

What if I discover additional errors after filing?

Use Form 1120X to file an amended corporate return. The deadline for amendments is generally three years from when the original return was filed or two years from the date tax was paid. While refunds for 2018 may no longer be available, corrections help align corporate tax records.

Will filing late affect future years?

Yes. Unfiled or late 2018 returns can affect NOL carryforwards, estimated tax requirements, and IRS audit selection. Filing now reduces exposure to additional penalties and helps maintain accurate records for future filings. The IRS may scrutinize subsequent returns more closely if prior-year returns remain delinquent.

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