mortgage backed securities

In finance, a mortgage-backed security (MBS) is an asset-backed security whose cash flows are backed by the principal and interest payments of a set of mortgage loans. Payments are typically made monthly over the lifetime of the underlying loans.Residential mortgagors in the United States have the option to pay more than the required monthly payment (curtailment) or pay off the loan in its entirety (prepayment). Because curtailment and prepayment affect the remaining loan principal, the monthly cash flow of a MBS is not known in advance, and therefore presents an additional risk to MBS investors.
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Securities backed by a pool of mortgage loans.