Interchange

When a customer pays by card, your processor's bank pays interchange to the bank that issued the card. Networks such as Visa and Mastercard set the rates. The cost reaches you as part of the merchant discount you pay on each transaction.

Rates vary by card type and by how the sale was made. Mastercard lists factors such as your merchant category, the time between authorization and clearing, the transaction data submitted and your card volume, and it updates its rates periodically.

You cannot negotiate interchange itself. You can control the markup your processor adds and how you capture sales, which is why interchange-plus pricing, where the 2 are shown separately, is easier to audit.