Yields on Fannie Mae and Freddie Mac mortgage securities that guide U.S. home-loan rates reached the highest relative to 10-year Treasuries since May, as investors speculate that supply may grow as homeowner refinancing rises. Fannie Mae’s current-coupon 30-year fixed-rate mortgage bonds rose 0.05 percentage point to 0.91 percentage point more than 10-year Treasuries as of 1:58 p.m. in New York, data compiled by Bloomberg show. The gap reached a record low of 0.54 percentage point on July 30.