Prepayment speeds on discount mortgages increased significantly over the last couple of years as a result of structural changes in the mortgage market, changing borrower attitudes toward mortgage debt, and extraordinary home price appreciation, according to Bear Stearn’s latest analysis of short-term prepayment estimates. The report noted that discount mortgage prepayment speeds for seasoned pools have changed during each of the three periods that preceded significant refinancing waves over the last 12 years. The…