In 2006-2007 a group of investors bet against the United States mortgage market. In their research, they discover how flawed and corrupt the market is.In 2006-2007 a group of investors bet against the United States mortgage market. In their research, they discover how flawed and corrupt the market is.In 2006-2007 a group of investors bet against the United States mortgage market. In their research, they discover how flawed and corrupt the market is.