According to the Mortgage Bankers Association’s Weekly Applications Survey, mortgage application activity for both refinancing and purchase jumped 15.5 percent last week from the week before. It was the largest increase in four months. The spike in demand was driven by a 23.1 percent increase in the Refinance Index. Michael Fratantoni, MBA’s vice president of research and economics, said mortgage rates were back to their lowest levels of the year and refinance applications surged in response. The average contract interest rate for 30-year fixed-rate mortgages fell to 4.54 percent from 4.55 percent the week before. More here and here.