SPEI® is a large-value funds transfer system in which participants can make transfers among themselves on behalf of themselves or their customers. Each payment order contains information allowing identification of the sender client and the client to whom the payment should be credited. The system began operating on August 13, 2004.

Within the system, participants may assign high priority to some payments and reserve part of their account balance to settle only these payments. As payment orders enter the system, they are kept in a pending-payments queue. SPEI® runs a process frequently - on the order of seconds - to decide which payments can be settled with the participant balances held at the moment. If a payment cannot be settled due to a sender´s lack of liquidity, the payment is held in the queue until the next cycle in the process.

Participant banks must send customers payment orders to recipient banks within 30 seconds after an order is made. Recipient banks must credit payments to their customers within 30 seconds after a payment is received.

Pending payments are canceled at the end of the day. Afterwards, the SPEI® account balances are transferred to the corresponding accounts in the SIAC system.

Safety in the SPEI® system is based on digitally signed messages. Participants must use authorized digital certificates and passwords obtained in accordance with the rules of the Public Key Infrastructure (Infraestructura Extendida de Seguridad) developed by Banco de México.

SPEI® uses an open protocol (i.e., system communication rules are public). The protocol allows participants to develop automatic processes and provides more and improved services to their customers.

In order to incentivize using SPEI® and recover the costs involved in operating this system, Banco de México has established a scheme in which participants pay Banco de México a fixed fee that allows them to send and receive an unlimited amount of payments. This fixed fee is calculated by distributing among participants the system costs on the basis of the relative proportion of each participant’s payments in the total number of payments done through the system during a specific period.

Participants must also pay an operations fee, calculated on the basis of the number of payment orders sent, the returns for which a participant is liable, money transfer orders done through CLS, and the amount of bytes retransmitted by SPEI® at a participant’s request.

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