Mexico's tax authority SAT tightens digital invoicing rules and sets 2026 Buzón Tributario deadline

The Servicio de Administración Tributaria (SAT) released on 9 July the first set of modifications to the 2026 Miscellaneous Fiscal Resolution, affecting the hydrocarbon sector and all taxpayers. The rules tighten conditions for the Digital Seal Certificate (CSD), allowing the authority to restrict its use and block electronic fiscal receipts (CFDI) for service stations that do not promptly correct irregularities. The resolution also requires the fuel‑invoicing complement in CFDI and updates technical specifications in Annexes 21 and 22, which govern volumetric controls for fuel tax incentives. Metroenergy advises station operators to review their billing systems and volumetric controls to ensure compliance.

Separately, the SAT imposed a deadline of 31 December 2026 for all registered taxpayers to enable or update their Buzón Tributario, the official electronic mailbox for tax communications. Non‑compliance will trigger fines ranging from MXN 3,850 to MXN 11,540, effective 1 January 2027, and may lead to notifications by service of process. Taxpayers must keep a valid email address and mobile phone number on file, with limited exemptions for low‑income individuals and inactive entities.