Acquirer Reference Number

An ARN is generated by the acquirer at the point of settlement and assigned to every processed card transaction. The 23-digit number encodes specific information: the first 6 digits identify the acquiring bank, the next 4 digits represent the Julian date of processing, and the remaining digits form a unique sequence number within that batch. This structure means an ARN is globally unique to a single transaction and carries enough encoded information to identify the processing bank and date without external reference.

The primary operational use of ARNs is in dispute and refund tracing. When a cardholder contacts their issuing bank to query a transaction, the issuer can use the ARN to trace the payment through the card network back to the acquirer and merchant. This tracing capability is what allows issuers to verify transaction details, confirm that a refund has been processed, and retrieve documentation for chargeback investigation. Without an ARN the tracing process requires manual escalation through the card scheme.

For merchants, the ARN is particularly valuable in customer service scenarios involving refunds. When a merchant processes a refund, the refund is assigned an ARN by the acquirer. If a cardholder disputes that a refund was received, the merchant can provide the ARN to the cardholder, who can then present it to their issuing bank to trace the refund through the network. This is often faster than waiting for chargeback proceedings and can resolve the dispute without a formal chargeback being filed.

ARNs are available in the acquirer's transaction reporting and settlement files. Merchants should ensure their customer service and finance teams know how to retrieve and communicate ARNs, as this capability directly reduces the number of preventable chargebacks that arise from refund disputes.

Providing an ARN when a customer disputes a refund enables the issuer to trace the refund credit instantly, often resolving the dispute before a formal chargeback is filed. The ARN for a processed refund is the definitive proof that the refund was submitted to the card network; it is stronger evidence than an internal system record. Acquirers and card schemes use ARNs to retrieve transaction documentation during chargeback investigation; merchants who include ARNs in dispute responses accelerate the resolution timeline. Communicating the ARN to a cardholder for a refund they claim not to have received shifts the tracing responsibility to the issuer and removes the merchant from the middle of the investigation. ARNs provide a reliable join key between the merchant's order management system and the acquirer's settlement file, enabling precise transaction-level reconciliation.