Under  certain  circumstances,  the  Trustee  has  the  option  to  purchase  the  Trust  Assets,  thereby effecting  early  retirement  of  the  Securities.  See “Description of the Securities — Termination” in this Supplement. Accretion Directed Classes Class FA and Z are Accretion Directed Classes. The related Accrual Amount will be applied to making principal distributions on these Classes as described in this Supplement. Class SA is a Notional Class whose Class Notional Balance is determined by reference to the Class Principal Balance of FA. Each of Class FA and Z has the AD designation in the suffix position, rather than the prefix position, in its  class principal type because it does not have principal payment stability through the applicable pricing prepayment assumption. Although the Accretion Directed Classes are entitled to receive payments from the related Accrual Amounts, they do not have principal payment stability through any prepayment rate significantly higher than 0% PSA. Securities that Receive Principal on the Basis of Schedules As described in this Supplement, the TAC Class will receive principal payments in accordance with a  schedule  calculated  on  the  basis  of,  among  other  things,  a  Structuring  Rate.  See “Terms Sheet — Scheduled Principal Balances.”  However, whether such Class will adhere to its schedule and receive “Scheduled  Payments”  on  a  Distribution  Date  will  largely  depend  on  the  level  of  prepayments experienced by the Mortgage Loans. The TAC Class exhibits an Effective Rate of constant prepayment rates at which such Class will receive Scheduled Payments. That rate may differ from the Structuring Rate used to create the related principal balance schedule. Based on the Modeling Assumptions, the initial Effective Rate for the TAC Class is as follows: TAC Class Initial Effective Rate FA  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366% PSA •  The principal payment stability of the TAC Class will be supported by the Support Class. If  the  Class  supporting  the  TAC  Class  is  retired  before  the  TAC  Class  is  retired,  the outstanding TAC Class will no longer have an Effective Rate and will become more sensitive to prepayments on the Mortgage Loans. There  is  no  assurance  that  the  Mortgage  Loans  will  have  the  characteristics  assumed  in  the Modeling Assumptions, which were used to determine the initial Effective Rate. If the initial Effective Rate  was  calculated  using  the  actual  characteristics  of  the  Mortgage  Loans,  the  initial  Effective  Rate could differ from that shown in the above table. Therefore, even if the Mortgage Loans were to prepay at  the  initial  Effective  Rate  shown  for  the  Class  in  the  above  table,  that  Class  could  fail  to  receive Scheduled Payments. Moreover, the Mortgage Loans will not prepay at any constant rate. Non-constant prepayment rates can cause the TAC Class not to receive Scheduled Payments, even if prepayment rates average the Effective Rate, for that Class. Further, the Effective Rate for the TAC Class can change or cease to exist depending on the actual characteristics of the Mortgage Loans. If the Mortgage Loans prepay at rates that are generally below the Effective Rate for the TAC Class, the  amount  available  to  pay  principal  on  the  Securities  may  be  insufficient  to  produce  Scheduled Payments on such TAC Class, and its Weighted Average Life may be extended, perhaps significantly. S-13