Pass through fees are fees assessed to acquiring banks by the Payment Card Networks (Visa, MasterCard, Discover, and American Express) which are then “passed through” to merchants by each payment processing provider.
These are primarily non-negotiable for merchants. Pass through fees make up the large majority of the overall merchant discount rate.
The most common pass through fee is Interchange, also known as IC or IRF. Interchange is the amount that Acquirers such as First Data Canada are required to pay Card Issuers by way of the Payment Card Networks such as Visa, MasterCard, Discover and American Express for each credit or debit card transaction you process. Interchange rates are set and regulated by the Payment Card Networks and can vary by method of acceptance, the type of business accepting cards (MCC), type of card, whether it is face-to-face, or many other variables.