New York CNN  —  A federal judge overseeing a $30 billion preliminary swipe-fees settlement between Mastercard, Visa and retailers formally rejected the deal Tuesday. Mastercard and Visa, two of the world’s largest credit card networks, reached their proposed multi-billion antitrust settlement with US merchants in March. The settlement would lower swipe fees, or interchange fees, that a retailer must pay when a customer makes a purchase using their card. Retailers typically are charged 2% of the total customer transaction in swipe fees — but they can be as much as 4% for some premium rewards cards, according to industry estimates. The proposed settlement would have lowered those fees by at least 0.04% percentage points for a minimum of three years. This is a developing story and will be updated.