The Federal Reserve is preparing to raise its benchmark interest rate for the first time since 2006. Because policy makers have signaled they will raise their key rate slowly and incrementally, potential buyers are less likely to rush into the market ahead of the first rate hike, said Columbus, Ohio-based Nationwide Insurance Chief Economist David Berson. Besides, mortgage rates, while no longer at a record low, are still half their historical average in Freddie Mac data back to April 1971.