According to Wal-Mart, Visa's credit card swipe fees violate antitrust regulations and have cost retailers and shoppers more than $350 billion.
This isn't the first time credit card companies have been taken to court over high fees. In 2012, Visa and Mastercard reached a $7 billion settlement with retailers and agreed to lower their fees. However, Wal-Mart, Target, and Amazon opted out of the settlement.
Wal-Mart has not made any mention yet on whether they will bring a similar suit against MasterCard.