Retailers are busy with the holiday shopping season, but that doesn't mean they don't have time to contest a settlement they find unfair.

Earlier this month, U.S. District Judge John Gleeson granted preliminary approval to what could be the largest antitrust settlement in U.S. history. The $7.2 billion deal between a class of retailers, Visa Inc., MasterCard Inc. and several banks would resolve seven years of litigation concerning allegations that the credit card companies and banks conspired to fix credit and debit card use fees—also known as swipe fees. Stores are charged fees every time a customer makes a purchase using a card, resulting in more than $30 billion in swipe fees a year. Under the terms of the settlement, which would cover nearly 8 million merchants, the defendants would pay $6 billion to the class and reduce the swipe fees for eight months, which would result in $1.2 billion in savings.

Gleeson approved the deal despite objections from retailers such as Wal-Mart Stores Inc. and Target Corp., as well as the National Association of Convenience Stores. Now, some of the retailers and trade groups that are part of the settlement are officially challenging Gleeson's order. Yesterday, 10 stores and trade groups filed notice that they're appealing Gleeson's order to the 2nd Circuit. The plaintiffs say the settlement violates their rights by preventing them from opting out. They are challenging a portion of Gleeson's order that would release Visa and MasterCard from new legal claims over related issues.

Read Bloomberg Businessweek and Thomson Reuters for more about the appeal.

For more InsideCounsel coverage of the Visa/MasterCard settlement, read: