Single-family mortgage securitization by Fannie Mae and Freddie Mac increased sharply during the third quarter of 2012, according to a new Inside Mortgage Finance ranking and analysis. New production of mortgage-backed securities by the two government-sponsored enterprises rose 22.4 percent from the second quarter, driven by a hefty 19.4 percent increase in refinance business. Refinance loans accounted for 76.9 percent of GSE securitization during the period, and the dollar volume of refi loan sales rose 19.4 percent from the second quarter. Fannie posted...[Includes three data charts]