The U.S. Justice Department announced last week that a long-running antitrust investigation against the three largest card brands has ended in a settlement with two of the three and litigation against the third.

The Justice Department's complaint is that American Express, Visa and MasterCard have put rules in place that prevent merchants from offering consumer discounts, rewards and information about card costs to induce them to choose another payment method. Visa and MasterCard have filed a proposed settlement to the charges that a court will have to approve. American Express had not yet filed a response to the charges, but a statement from the card brand indicated it intends to fight the charges in court.

"With today's lawsuit, we are sending a clear message: We will not tolerate anticompetitive practices," said U.S. Attorney General Eric Holder when the complaint was filed on Oct. 4. "We want to put more money in consumers' pockets, and by eliminating credit card companies' anticompetitive rules, we will accomplish that."