Fannie Mae raised a few eyebrows back in September when it reclassified a huge $135 billion of securities held in portfolio from held-to-maturity to available-for-sale. And while there was some speculation that Fannie made the change in order to better meet its new risk-based capital requirements, GSE officials dismissed these suggestions. They maintained the reclassification was simply an accounting change that gave the company more flexibility in managing its massive mortgage portfolio.