
When Your EIN Gets Stolen: A Small Business Guide to IRS Letters 5263C, 6042C, and Business Identity Theft
IRS Letter 6042C verifies a specific business return; Letter 5263C verifies the entity itself on file from Form SS-4, and both carry a 30-day response window that, if missed, stalls your returns, refunds, and overpayment applications. This guide explains how thieves obtain an EIN, the tax and non-tax red flags that signal fraud, exactly what to fax back in each case, when Form 8822-B is required within 60 days of a responsible-party change, and a monthly-quarterly-annual monitoring routine that catches misuse early.










