Brussels, Belgium (BBN)-European Union officials have accused MasterCard of overcharging consumers with the fees it charges.
"We currently suspect MasterCard is artificially raising the costs of card payments," said the EU statement.
Those fees harm consumers and retailers in the EU, reports BBC quoting competition commissioner Margrethe Vestager as saying.
The credit card company said it was "working with the European Commission on the issue" and was preparing a formal response.
"Throughout this procedure we have kept the needs of both consumers and merchants in mind," MasterCard said.
Today's objections from the EU are part of a long-running investigation.
The EU is focusing on what is known as 'interchange fees' - the fees retailers pay banks to process card payments.
A separate investigation into Visa's interchange fees is also being carried out by the EU.
BBN/ANS