IRS Letter 12C: Return incomplete — information needed

Quick answerThe IRS needs more information to finish processing your return. A common reason is a missing Form 8962 for marketplace health insurance.

Letter / notice12C

MeaningReturn incomplete — information needed

Action needed?Yes — see steps

What happens next

Respond by the date in the letter; processing restarts once the IRS gets your answer.

What you should do

Send exactly what the letter asks for, with a copy of the letter
Do not file an amended return in response

IRS Letter 12C explained: Return incomplete — information needed — what it means and what to do next — Save this quick guide for later — share it or pin it.

Scam check: the IRS first contacts you by mail. Use only the phone numbers printed on your letter or on IRS.gov — never ones from a text, email or unofficial site.

Frequently asked questions

What does IRS Letter 12C mean?

The IRS needs more information to finish processing your return. A common reason is a missing Form 8962 for marketplace health insurance.

What should I do?

Send exactly what the letter asks for, with a copy of the letter Do not file an amended return in response

How long does it take?

Respond by the date in the letter; processing restarts once the IRS gets your answer.

Sources

Written by the editorial team and checked against the official sources above. See our editorial policy.

By the TranscriptCodes Editorial Team · Last reviewed 2026-11-12.