Heartland revealed last January that malicious software in its processing system had been found, potentially compromising the card data of millions of people.

The $5 million settlement with Discover follows a $41.4 million pay-out to MasterCard, a $60 million bill from Visa and a $3.6 million deal with American Express. In Dember last year the embattled processor also agreed to pay up to $2.4 million to settle a consumer cardholder class action suit

Announcing the latest agreement, Bob Carr, Heartland's chairman and chief executive officer, says: "This settlement marks our final agreement with a card brand related to the intrusion."