Wal-Mart gets new ammo in Web battle with Amazon By: CNBC.com News May 12, 2015 at 09:00 AM EDT Wal-Mart is teaming up with messaging start-up Tango as it seeks to lure mobile commerce users from powerful rival Amazon.com. Read More >> Related Stocks: Alibaba Group Holding Ltd Amazon.com Facebook Lendingclub Corp Tencent Holdings ADR Wal-Mart Stores, Inc. Yahoo