The regulation limits interchange fees for covered consumer card transactions and changes business rules that can restrict competition. Its principal caps are 0.2% of transaction value for consumer debit and 0.3% for consumer credit, with specific options and conditions affecting the debit framework. The interchange fee is the amount exchanged between issuing and acquiring sides; it is only one component of the merchant's overall acceptance cost.

Scope is essential. The cap framework distinguishes consumer and commercial cards, four-party arrangements and the treatment of certain three-party schemes. It is not a universal cap on every card transaction worldwide. The regulation also addresses the separation of card-scheme and processing activities, co-badging, choice of payment application, merchant information and restrictions on steering or selective acceptance.

Its practical effect is to make both the price structure and the allocation of choice more contestable. A merchant can still pay acquiring, processing and other service charges, so a merchant service charge above the interchange cap does not alone show a breach. Assessing a transaction requires its card category, geography, scheme structure and the particular fee or business rule at issue.