Letter 4883C: Potential Identity Theft during Original Processing
Taxpayer Protection Program notification to a taxpayer to verify their return by phone. Advises taxpayers that a return was received with their name and Social Security Number (SSN) and that to protect them from identity theft, their identity needs to be verified before processing the return. Taxpayers receiving this letter are required to call the TPP telephone line to authenticate their identity.
Updated: July 15, 2025