According to this article by Bloomberg reporter William Pesek, Asian investors, who own a huge amount of agency debt, are getting worried about the soundness of Fannie and Freddie. Freddie has recently been rocked by an accounting scandal. In spite of the denials by Fannie and Freddie that their securities are government-guaranteed, the Asian markets think that they are and this is one of their main appeals.
If the Asian central banks were to start to unload these securities in volume, that would put a serious downware pressure on the dollar, the US mortgage market, and the remaining pillars of the stock market/credit/real estate bubbles.
