The National Banking and Securities Commission (CNBV) in Mexico updated regulations to include SMS as a permitted channel for sending Category 3 authentication factors. ^[1] Mexican banks will implement SMS-based authentication for specific financial transactions starting September 2, 2026. ^[2] Previously, Category 3 authentication factors were restricted to encrypted email or secure instant messaging services. ^[3] The new regulation applies to services provided by technology-based intermediaries (comisionistas de base tecnológica) in Mexico. ^[4] The specific operations covered include opening Level 2 accounts, transfers up to 3,000 UDIS (equivalent to 26,434.79 Mexican pesos), and payments for goods and services. ^[5] The new regulation allows text messages to serve as a Category 3 authentication factor to verify account ownership for high-security operations. ^[6] The regulation applies to base technology agents offering services including account openings, loans up to 3,000 UDIs, payments, and balance inquiries. ^[7] Banks must provide clear and visible options on their websites or agent applications for customers to update their registered phone numbers for receiving SMS codes. ^[8]