Understanding Your Letter 12C

We need additional information from you to process your tax return.

We are sending you this letter because we need more information to complete the processing of your individual income tax return. This information can include:

  • Missing forms or schedules to support your entries on Form 1040, 1040-A, or 1040-EZ
  • Verification of income, withholding, and credit amounts
  • Documentation to reconcile advance payments of the Premium Tax Credit (PTC). Please refer to PTC page for more information about letters regarding advance payments of the PTC.

What you need to do

  • Read your letter carefully and respond timely.
    • Respond to the letter, even if you disagree with the information in the letter. If you disagree, send us a letter explaining what information you think is in error. Provide the information requested in the letter.
  • Do not file a Form 1040-X, Amended U.S. Individual Income Tax Return. After we receive the requested information, we’ll use it to process your original tax return.
  • If you’re entitled to a refund, we’ll send it about 6-8 weeks from the time we receive your response.

How to respond

Your letter 12C provides a fax number, if you want to send the information by fax. If you prefer to mail your response, send the information to the address listed at the beginning of the letter. Also, include a copy of the letter with your response.

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