The current financial crisis occurred after a long and remarkable period of growth and innovation in our financial markets. New financial instruments allowed credit risks to be spread widely, enabling investors to diversify their portfolios in new ways and enabling banks to shed exposures that had once stayed on their balance sheets. Through securitization, mortgages and other loans could be aggregated with similar loans and sold in tranches to a large and diverse pool of new investors with different risk preferences. Through credit derivatives, banks could transfer much of their credit exposure to third parties without selling.
