The Federal Housing Finance Agency is keeping a close eye on large-scale servicing transfers because it is concerned about capacity issues that might arise from smaller players taking down portfolios that significantly increase their overall processing volume. According to industry advisors and servicing executives familiar with the issue, FHFA played a key role in Bank of Americas recent sale of $306 billion of mortgage servicing rights to Nationstar Mortgage and Walter Investment Management Corp. One source familiar with the deal said FHFA asked that Nationstar not take down the entire portfolio and that it be broken up into more than one piece. A spokeswoman for FHFA declined to comment on the matter to Inside The GSEs.