Citibank was founded in 1812 as the City Bank of New York, later First National City Bank of New York. Citibank is one of the major international banks in the United States. It is the consumer banking sector of financial services giant Citigroup. Citigroup was the third largest bank holding company in the United States by total assets, after Bank of America and JPMorgan Chase in 2010 ("Top 50 banks”, 2011). Citibank has retail banking operations in more than 160 countries and regions around the world which has more than 200 million customer services. Citibank is the world's largest credit card issuers and covers various financial products in many fields, from consumer finance to corporate finance, from the credit card business to the investment business, etc.
During the period of global financial crisis of 2008-2009, Citibank suffered massive losses in the value of its subprime mortgage assets because many CDOs backed by subprime mortgages the bank held. Meanwhile, bond default insurance and subprime mortgage bond are closely bounded up. Bond default insurance (CDS, one of the financial derivatives) market is quite huge which has reached $ 62 trillion in 2007. Citibank held nearly $ 4 trillion bond default insurance until the end of 2007 which accounted for 6% of the whole market. Furthermore, the main credit collateral of the bank