Understanding Your Letter 12C


What this letter is about

We are sending you Letter 12C because we need more information to process your individual income tax return. This information can include:

  • Missing forms or schedules to support your entries on Form 1040 or Form 1040-SR
  • 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 on PTC advance payments.  

What you need to do

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

How to respond

  • Fax your information to the fax number in the letter using either a fax machine or an online fax service. Protect yourself when sending digital data by understanding the fax service’s privacy and security policies.
  • You can also mail your information to the address shown at the top of the letter.
  • Include a copy of the letter with your response.

You may want to

Visit our Affordable Care Act page for more information about filing a tax return with Form 8962, Premium Tax Credit (PTC).

More information you may find useful