Wal-Mart is suing Visa for $5 billion dollars for allegedly conspiring with banks to illegally inflate credit card processing fees. 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.