What This Letter Means
Letter 178C tells you the IRS received your amended return but can't process it as filed. Something required is missing: a signature, a form or schedule that supports the change, the tax year, a Social Security number, a dependent's information, or an explanation of what you changed and why.
This letter is generally used when your amended return shows a refund or no change in the balance. The letter explains exactly what is missing. Common examples:
- No tax year on the Form 1040-X, or several years combined on one form. Each year needs its own amended return.
- A missing or invalid Social Security number for you, your spouse, or a dependent.
- A missing schedule that supports the change, such as Schedule A, Schedule EIC, or Schedule SE.
- No explanation of the changes.
What to Do
- Read the letter for the specific item. In many cases the IRS asks you to submit another Form 1040-X with the missing piece included.
- Send everything at once. Include a copy of the letter so your reply is matched to your account.
- Keep copies of everything you send, and use certified mail if you reply on paper.
Why Timing Matters
When you send the missing information, the IRS treats the date it receives your reply as the received date of your amended claim. Not the date of your original filing. If you are close to the deadline for claiming a refund for that year, a slow reply can cost you the refund. Respond quickly.
If You Don't Respond or the Reply Is Incomplete
If your reply still leaves items missing, the IRS adjusts only what it can process and sends a letter explaining what it did not allow. If nothing can be processed, you get a letter saying your claim was not considered. Either way, you lose the part of the claim you didn't support.
If you received Letter 178C and your refund claim is on the line, call us at (813) 229-7100.