Acquirer reference number (ARN)

What is an acquirer reference number?

An acquirer reference number, or ARN, is a unique reference number assigned to a card transaction as it moves through the acquiring bank, card network, and issuing bank.

ARNs are commonly used to track card payments, refunds, and some dispute-related transaction flows. They help payment providers, acquirers, issuers, merchants, and banks identify a specific transaction after it has been processed.

In simple terms, an ARN is a tracking number for a card transaction.

How an ARN works

An ARN is usually generated after a card transaction has entered the clearing or settlement process. It can be used to trace where the transaction is in the payment flow and confirm whether it has reached the issuer or cardholder's bank.

For example, when a merchant issues a refund, the customer may not see the money immediately. The ARN can help the acquirer, PSP, or issuing bank locate the refund and check its processing status.

ARNs are especially useful when a transaction has already been approved or refunded, but the customer, merchant, or support team needs to understand what happened after processing.

When is an ARN used?

An acquirer reference number may be used for:

• tracking card refunds;
• checking payment settlement status;
• investigating missing or delayed refunds;
• supporting customer service requests;
• helping issuers locate a transaction;
• matching transaction records between providers and banks;
• supporting dispute or chargeback investigations.

For merchants, ARNs are most often useful when a customer asks where a refund is or when a payment needs to be traced through the card payment chain.

After a refund is processed, the merchant or payment provider may receive an ARN that can be shared with the customer or their issuing bank. The issuer can use this number to locate the refund and check whether it has been received, posted, or is still pending.

The ARN does not make the refund instant. Refund timing still depends on the card network, issuer, acquirer, payment provider, and banking processes.

Acquirer reference numbers give teams a transaction-level reference for tracing processed card payments and refunds.