Fannie Mae and Freddie Mac continued to wrangle with mortgage sellers over repurchase requests during the fourth quarter of 2012, mostly over loans originated five years earlier, according to a new Inside Mortgage Finance analysis of disclosures by the two government-sponsored enterprises. As the year ended, the GSEs had a whopping $20.11 billion in pending and disputed buyback requests with lenders, up 9.5 percent from the end of the third quarter. While Freddie actually managed to whittle down its stack of unresolved cases by 1.1 percent, the pile grew 10.5 percent higher at Fannie. And 52.1 percent of these disputes involved loans securitized in 2007. The dollar volume of loan repurchases and indemnifications edged...[Includes one data chart]