[us mortgage rates rise to a two-month high of 6.57%] FAP, May 26, US mortgage rates rose to their highest level since mid-March. Freddie Mac said in a statement on Thursday that interest rates on 30-year fixed mortgages averaged 6.57%, up from 6.39% last week. The interest rate jumped with Treasury yields as investors were closely watching the impasse in the federal debt ceiling negotiations. Borrowing costs are close to their highs at the end of last year, adding to the burden on buyers struggling to find affordable housing amid a dearth of inventory of second-hand homes. New homes account for a growing proportion of transactions because homeowners who bought at historically low mortgage rates are reluctant to move and trade.