The CLABE (Clave Bancaria Estandarizada, Spanish for "standardized banking cipher" or "standardized bank code") is a banking standard for the numbering of bank accounts in Mexico. This standard is a requirement for the sending and receiving of domestic inter-bank electronic funds transfer since June 1, 2004. ¿Qué es la CLABE? (abm.org.mx) (Spanish)
The CLABE replaces the old Mexican account numbering scheme where the account number had 11 digits. The provision for CLABE standardization was issued by the Asociación de Bancos de México (ABM) (Mexican Bank Association) in conjunction with the Banco de México (Mexico's Central Bank). It ensures that the inter-bank fund transfers, payroll deposits, or automatic service charges are made to the correct accounts.