Each of the Accretion Directed Classes 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, each PAC and TAC Class will receive principal payments in accordance with a schedule calculated on the basis of, among other things, a Structuring Range or Rate. See "Terms Sheet – Scheduled Principal Balances." However, whether any 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 related Mortgage Loans. Each PAC and TAC Class exhibits an Effective Range or Rate of constant prepayment rates at which such Class will receive Scheduled Payments. That range or rate may differ from the Structuring Range or Rate used to create the related principal balance schedule. Based on the Modeling Assumptions, the initial Effective Ranges or Rate for the PAC and TAC Classes are as follows: Initial Effective Ranges PAC Classes PF and PO (in the aggregate) ...................................... 100% PSA through 260% PSA YA, YB and YC (in the aggregate) .............................. 120% PSA through 200% PSA Initial Effective Rate TAC Class FC*  ...................................................................................... 122% PSA *  Structured at an assumed LIBOR of 5.12%. At LIBOR levels less than 5.12%, Class FC will no longer have an Effective Rate. •   The principal payment stability of the PAC I Classes will be supported by the related PAC II and Support Classes. •   The principal payment stability of the PAC II Classes will be supported by the related Support Classes. •   The principal payment stability of the TAC Class will be supported by the related Support Class. If all of the Classes supporting a given Class are retired before the Class being supported is retired, the outstanding Class will no longer have an Effective Range or Rate and will become more sensitive to prepayments on the related Mortgage Loans. There is no assurance that the related Mortgage Loans will have the characteristics assumed in the Modeling Assumptions, which were used to determine the initial Effective Ranges or Rate. If the initial Effective Ranges or Rate were calculated using the actual characteristics of the related Mortgage Loans, the initial Effective Ranges or Rate could differ from those shown in the above tables or an initial Effective Rate might not exist. Therefore, even if the Mortgage Loans  were  to  prepay  at  a  constant  rate  within  the  initial  Effective  Range  or  at  the  initial Effective Rate shown for any Class in the above tables, that Class could fail to receive Scheduled Payments. It is not likely that LIBOR will remain at the constant level set forth in the modeling assumption for Class FZ, which was used to determine the Initial Effective Rate for Class FC. If S-15