Fannie Mae and Freddie Mac saw a 27.2 percent surge in refinance business during the fourth quarter that helped offset an 8.3 percent drop in purchase-mortgage acquisitions, according to an Inside Mortgage Trends analysis of mortgage-backed securities data. The wholesale-broker channel recorded a 7.4 percent increase in production during the fourth quarter, compared to smaller increases in retail (2.6 percent) and correspondent (6.0 percent) ... [Includes one data chart]