Interchange++
A card-acceptance pricing model in which the merchant sees and pays the three cost components separately, rather than one blended percentage.
Every card transaction carries three costs: the interchange fee to the issuer, the card network's own scheme fees and the acquirer's markup. Under blended pricing the acquirer rolls all of that into one rate. It's easy to understand, but the acquirer profits on every cheap debit card and loses on every pricey corporate one. Under interchange++ (or IC++) the items are itemised: interchange, plus scheme fees, plus the acquirer's margin.
The model favours high-volume merchants with lots of domestic debit cards, where the interchange cap makes the first line almost negligible. EU Regulation 2015/751 requires acquirers to offer unbundled pricing. The downside is a statement that needs a spreadsheet to read, and scheme fees have a way of multiplying in line items nobody audits.