Any businesses that handles credit card processing has undoubtedly been following the lawsuit that was filed in 2005 against Visa and MasterCard. It was filed by several merchants and trade organizations alleging the credit companies were charging unlawful excessive swipe and processing fees. In 2012, Visa and MasterCard agreed to settle and phase two – decided on the terms – began.

That seemingly came to an end on December 13, 2013, when U.S. District Judge John Gleeson agreed on a $5.7 billion settlement. However, in the month since the announcement, several merchants have decided to appeal the decision, despite receiving money from it.

According to a recent article from Business Insider, American Express is the latest to jump on board the appeal, joining Wal-Mart, Amazon, 7-Eleven and Barnes and Noble, among others that have already filed.

The reason for the appeal is two fold. First off, there are some who believe the settlement number is too low.

The National Retail Federation expressed disappointment and frustration with the decision, saying it forces merchants to accept a settlement they do not agree with and will ultimately do little to protect their rights and their customers' finances from something like this happening again.

"The language of the release that Visa and MasterCard required in their settlement is so broad that defendants in that case could argue that it applies to claims of competitors, not just merchants," Marina Norville, vice president of public affairs and communications at AmEx, told the news source.

Any credit card payment processor needs to keep an eye on the outcome of this lawsuit as it will have ramifications for the retail industry.