These securitization trusts include government-sponsored enterprises and private entities which may offer credit enhancement features to mitigate the risk of prepayment and default associated with these mortgages. Since residential mortgages in the United States have the option to pay more than the required monthly payment (curtailment) or to pay off the loan in its entirety (prepayment), the monthly cash flow of an MBS is not known in advance, and therefore presents risk to MBS investors.
