On the supply side, there were $5.63 trillion of single-family MBS guaranteed by Fannie Mae, Freddie Mac and Ginnie Mae outstanding at the end of September.
More than half of Fannie’s MBS flow in November came from refinance loans, the first time since March that purchase mortgages accounted for less than half of its business.
The key factor is that some mortgage originators, the megabanks especially, are keeping conventional loans in portfolio that might otherwise be securitized by Fannie and Freddie.