The CLABE (Clave Bancaria Estandarizada, Spanish for standardized banking cipher ) 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.The CLABE account code has 18 digits.he first 17 digits of the CLABE are, as mentioned above, the Bank Code, the Branch Office Code and the Account Number.