Fannie Mae’s short list to replace its outgoing chief executive has been narrowed down to two finalists – one leading candidate from within and another from outside the company. A source familiar with the inner workings of the company confirms published reports that Timothy Mayopoulos, Fannie’s chief administrative officer and general counsel, is the leading candidate among the GSE’s CEO search party.The company is also looking at S.A. Ibrahim, CEO of Philadelphia-based mortgage insurer Radian Group, as a strong contender for the top job.