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What is a System Trace Audit Number (STAN)

Sunday, December 06, 2015

When a customer requests a refund for an item, you may need to provide a System Trace Audit Number. This number, also referred to by the abbreviation STAN, is a valuable tool for tracking the status of a transaction and is similar to an Acquirer Reference Number (ARN). But what exactly is a STAN, and what is it for?

A STAN is a unique six-digit numeric code assigned to a credit card transaction as it moves through the payment flow. This data element is generated by the cardholder bank and is used to identify the transaction and is usually used for non-Visa and Mastercard credit card purchases. Though used to identify a transaction, a STAN is not the same as an account number.

How do STANs work?

The cardholder bank generates a STAN after a credit card transaction. This number is used as an identification number to track the status of a transaction through the payment flow and is most commonly used internally at the cardholder’s bank.

You won’t necessarily need to know the STAN for each purchase made through your business because this trace ID is usually only relevant in troubleshooting situations. These can include customer refund requests, missing payments, or transaction support.

STANs serve the same function as ARNs but are used less frequently. This could be because ARNs are generated for the more commonly accepted payment forms, Visa and Mastercard, instead of other credit card payments.

Before weighing the benefits of using an ARN vs. a STAN, let’s discuss the differences between these identification codes.

What are STANs used for?

STANs are typically only relevant when a customer requests a refund or if there’s an error in the transfer of funds from the bank. In these situations, the STAN gives the merchant or customer the ability to track the transaction and refund status. You may need to access a STAN for the following:

  • Electronic fund transfers
  • Credit card transactions
  • Debit card transactions
  • Partial settlements
  • Transfer of funds

Being aware of STANs is especially valuable if your business handles many transactions each day. While fraud isn’t a guaranteed eventuality, it’s prudent to be mindful of the possibility of fraud and monitor payment flow to detect card schemes early.

ARNs vs. STANs

We’ve already established that ARNs and STANs are acronyms that have something to do with credit card transactions, so what’s the difference between them?

An ARN or Acquirer Reference Number is similar to a STAN in that it is also a unique trace ID attached to a credit card transaction. Like STANs, an ARN is also used to tag a credit card transaction through the refund process as it goes from the acquirer, card network, issuer, and processor.

The ARN is sometimes referred to as an RRN or Retrieval Reference Number. It is a unique number generated for Visa and Mastercard purchases and is usually easier to locate than a STAN, even though it serves the same purpose.

An ARN is usually longer than a STAN, making it a more unique number. While a STAN is a six-digit code that rolls over after reaching 999,999, ARNs take longer to reach their roll-over limit.

While ARNs are usually tied to a Visa or Mastercard purchase, a STAN is typically associated with credit card transactions using a Discover card, either on your POS system or online. However, regardless of transaction type, STANs and ARNs serve the same purpose of tracking payment, transmission date, and transaction amount when a payment cancellation is requested.

When should customers use an ARN vs. a STAN?

In general, many merchants prefer to use an ARN where possible rather than STAN. The first main reason is that a STAN isn’t a wholly unique identification code. Because a STAN is a six-digit code, the counter restarts once the code reaches 999,999.

The other reason that ARNs are preferred is that they’re easier to find on most payment processing software dashboards, whereas locating the STAN usually requires contacting customer support.


A STAN is a unique number that is important for the security of credit card payments for any business. STANs prevent fraudulent charges by tracing unauthorized transactions and can give your customers peace of mind. In addition, if you need to offer a refund, STANs offer the convenience of being able to track the status of a refund throughout the entire process.

Issuing refunds is a part of any business, no matter how well you run it. A STAN is instrumental when a dispute arises and can protect your customers and your business. If your business accepts any credit card payments, it’s essential to understand what a STAN is, how to find it, and why it’s crucial to your business.

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