(July 13, 2012)--Visa, MasterCard and major banks have agreed to pay $7.3 billion to millions of merchants to end a dispute involving payments called interchange fees that merchants paid in credit card transactions.

The law firm representing the merchants said in a statement that about 7 million merchants were represented in the settlement.

Robins, Kaplan, Miller & Ciresi said the case is believed to be the largest settlement of a private antitrust case under the Sherman Act.

The class action suit stretches back to 2005, and involves most major U.S. banks as defendants.

The merchants include grocery chains Kroger Inc. and Safeway Inc., Rite Aid Corp., QVC Inc., the National Association of Convenience stores, and a long list of other trade groups and small merchants.