According to the Mortgage Bankers Association’s Weekly Applications Survey, refinance activity increased 13.5 percent last week and pushed the refinance share of all mortgage activity up to 75.2 percent. The spike in refinance activity helped the Market Composite Index, which measures total mortgage application volume, climb 6.9 percent from the week before despite a 11.2 percent drop in the Purchase Index. Jay Brinkmann, MBA’s chief economist, said a drop in rates last week led to the boom in refinance applications. The average contract interest rate for 30-year fixed-rate mortgages with conforming loan balances fell to 4.05 percent from 4.10 percent the week before. The drop in rates tied a survey low reached in early February. Also in the report, the average loan size of all loans for home purchase was $233,381 in March, up from $225,463 in February. More here.