Extension risk
the risk that prepayment will be slower than expected
Prepayment
A partial or full repayment of principal in excess of the scheduled principal repayment required by the mortgage
contraction risk
the risk that prepayment will be more rapid
The issuer of asset-backed securities is best described as the
SPV
Balloon risk
is the possibility that a commercial mortgage borrower will not be able to refinance the proncipal that is due at the maturity date of the mortgage