“…In the middle of July of 2008, two famous tycoons of mortgage loans in America, Freddie Mac and Fannie Mae, suffered a big loss of over 70 billion dollars and were taken over by US government in the end. However, the US government couldn't always be the saver [3]. With the rejection of saving Lehman Brothers Holdings, it finally broke down and aroused huge waves in financial market, domestically and internationally.…”