The LTR 431C is a request for supporting documentation during return processing. It's similar to the LTR 12C but often appears later in the processing cycle or when the IRS needs documents related to specific credits, deductions, or income items that couldn't be verified through their normal matching process.
What They Typically Request
The LTR 431C lists specific documents the IRS needs. Common requests include Forms W-2 or 1099 that the IRS didn't receive from the issuer, documentation supporting credits you claimed (education credits, child tax credit, earned income credit), proof of expenses for deductions, documentation of filing status (marriage certificate, divorce decree for head of household), and supporting schedules or forms that weren't attached to your return.
How to Respond
Read the request list item by item. Gather every document listed. Include the tear-off stub from the notice with your response so the IRS can match your documents to your account. Send everything to the address on the letter using certified mail with return receipt.
The single most important rule: send everything the first time. Partial responses add 8 to 12 weeks of processing time per round. If the letter asks for five items and you send three, you'll get another letter requesting the remaining two. That's another two to three months of waiting.
Processing Timeline
After the IRS receives your complete response, allow 6 to 8 weeks for processing. If your return was waiting for these documents, processing should resume after they're reviewed. If you're waiting for a refund, the refund clock restarts once your documents are accepted.
If you haven't heard anything after 8 weeks, call the number on the LTR 431C with your copies ready.
If you've received an LTR 431C, call us at (813) 229-7100 if you need help understanding what they're asking for.