By Dan Weil Does the move matter? Treasury yields have exploded and are likely to rise further amid rate increases by the Fed. As speculation arose in May that economic weakness might keep the Federal Reserve from raising interest rates much more, bond yields dipped. The 10-year Treasury slid from 3.12% May 6 to 2.74% on May 27. Investors were particularly moved by weak earnings reports from Walmart (WMT) – Get Walmart Inc. Report and Target (TGT) – Get Target Corporation Report. As Treasury yields determine mortgage rates, those rates briefly declined. The average 30-year fixed mortgage rate …