Credit and debit card fees are pushing up retail prices by as much as 2.5% in some EU markets, according to the European Commission.
Depending on where customers live in the EU, they could pay up to double in annual fees for a Visa or Mastercard
A ruling that Visa and Mastercard had violated antitrust law has been upheld by the US Supreme Court.
The case stemmed from a 1998 Justice Department lawsuit challenging the credit card issuers’ regulations.
The groups appealed after a court found they were wrong to block banks from issuing credit cards on rival networks such as Discover and American Express