This transaction set enables the electronic filing of tax return data between taxpayers, tax preparers, and tax authorities. Typically sent by tax preparation firms or corporate tax departments to government tax agencies or authorized filing intermediaries, the 813 communicates completed tax return information in a structured format. The BTI (Beginning Tax Information) segment establishes core filing details, while the TFS (Tax Form) segment within the optional detail loop identifies specific tax forms being transmitted. The TIA (Tax Information and Amount) segment carries detailed line-item tax data, amounts, and calculations that populate individual tax form fields.

For example, a mid-sized accounting firm like Anderson & Associates prepares corporate tax returns for their client TechCorp Industries and uses the 813 to electronically file TechCorp’s Form 1120-C return directly with the Internal Revenue Service. The transmission includes the BTI segment specifying the filing year and return type, multiple TFS segments identifying each form being filed (primary return plus schedules), and corresponding TIA segments containing TechCorp’s income, deduction, and tax liability amounts. The IRS receives the 813 transmission, validates the structured data against tax form requirements, and confirms receipt through an automated acknowledgment, streamlining the filing process compared to paper submission.