“Alt-A is sort of a weird mirror-image of subprime lending. If subprime was traditionally about borrowers with good capacity and collateral but bad credit history, Alt-A was about borrowers with a good credit history but pretty iffy capacity and collateral. That is to say, while subprime makes some amount of sense, Alt-A never made any sense. It is a child of the bubble.”
As a result fraud was rampant and it turns out, Prime, really isn’t.