Answer the entity-verification questions, including if you have no affiliation with the entity named.
Numbers covered by this guide
Letter 5263C
Letter 6042C
Check the identifier and follow the instructions on your own notice.
Editorially reviewed by the Law Offices of Darrin T. Mish, P.A.•Updated October 1, 2026
Notice
Letter 5263C / Letter 6042C
Urgency
Urgent
Deadline
Respond within 30 days of the letter date
Your first move
Answer the entity-verification questions, including if you have no affiliation with the entity named.
Why the IRS needs an answer
Letters 5263C and 6042C ask about a business, estate, or trust to verify EIN application information. Respond within 30 days of the letter date. If you are not affiliated with the entity, complete the no-affiliation response instead of ignoring it.
Check the requested attachments
Estate responses may require the death certificate; trust responses may require the Certificate of Trust or specified trust pages. Follow the actual letter's questions and transmission instructions. If you fax your response, the IRS says not to mail a duplicate.
Keep the submission organized
Label your retained copy with the EIN and letter date, and save delivery confirmation. Send only what the IRS requests through the verified channel; this website does not collect business-verification records.
This letter has a clock on it. Don’t run it out alone.
Free consultation with Darrin T. Mish, a Tampa tax attorney licensed since 1993 and admitted to the U.S. Tax Court. Bring the letter.