A few good cites will set the table for those willing to dig into what's really not that hard to understand...
In the mid-1990s mortgage bankers decided they did not want to pay recording fees for assigning mortgages anymore. This decision was driven by securitization—a process of pooling many mortgages into a trust and selling income from the trust to investors on Wall Street. Securitization, also sometimes called structured finance, usually required several successive mortgage assignments to different companies. To avoid paying county recording fees, mortgage bankers formed a plan to create one shell company that would pretend to own all the mortgages in the country—that way, the mortgage bankers would never have to record assignments since the same company would always “own” all the mortgages.
So if that isn’t fraud and racketeering what is?