During the final three months of 2012, Fannie Mae and Freddie Mac securitized some $52.72 billion of single-family home loans that were covered by private mortgage insurance, according to a new Inside Mortgage Finance analysis. That total represented 14.4 percent of the business done by the two government-sponsored enterprises during the fourth quarter – although there was significant variation among the GSEs’ top sellers in terms of the share of their deliveries covered by PMI. Some $8.42 billion of PMI-insured mortgages were pooled...[Includes one data chart]