AT&T Inc. and Verizon Wireless, the biggest U.S. mobile carriers, are planning a venture to displace credit and debit cards with smartphones, posing a new threat to Visa Inc. and MasterCard Inc., three people with direct knowledge of the plan said. The partnership, which also includes Deutsche Telekom AG unit T-Mobile USA, may work with Discover Financial Services and Barclays Plc to test a system at stores in Atlanta and three other U.S. cities that would let a consumer pay with the contactless wave of a smartphone, the people said. The carriers have been searching for a chief executive officer.

The trial would be the carriers’ biggest effort to spur mobile payments in the U.S. and supplant more than 1 billion plastic cards in American wallets. Smartphones have encroached on tasks ranging from Web browsing to street navigation and now may help the phone companies compete with San Francisco-based Visa and MasterCard, the world’s biggest payments networks.

“This is definitely a game-changer,” said industry consultant Richard Crone of San Carlos, California-based Crone Consulting LLC. The firm advises card networks, issuers and phone companies. The mobile carriers “are the biggest recurring billers in every market. They are experts at processing payments,” Crone said. Read full story in Bloomberg.