Class B-6 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of:

Class A Non-PO Optimal Principal Amount As to any Distribution Date, an amount equal to the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan, and (y) the sum of:

Class B-4 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of:

Class B-5 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of:

Class B-2 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of:

Class B-1 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of:

Class B-3 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of:

Senior Optimal Principal Amount For any Distribution Date and any Loan Group, the sum for all Mortgage Loans in such Loan Group of (i) the Senior Percentage of (a) the principal portion of each Scheduled Payment (without giving effect, prior to the Bankruptcy Coverage Termination Date, to any reductions thereof caused by any Debt Service Reductions or Deficient Valuations) due on each such Mortgage Loan on the related Due Date, (b) the principal portion of the Purchase Price of each such Mortgage Loan to the extent it was repurchased by the Transferor pursuant to this Agreement as of such Distribution Date, (c) the Substitution Adjustment Amount in connection with any Deleted Mortgage Loan related to such Loan received with respect to such Distribution Date and (d) any Liquidation Proceeds (including Insurance Proceeds) allocable to recoveries of principal of any Mortgage Loan related to such Loan Group that is not yet a Liquidated Loan, received during the calendar month preceding the month of such Distribution Date, (ii) with respect to each such Mortgage Loan in such Loan Group that became a Liquidated Loan during the calendar month preceding the month of such Distribution Date, the lesser of (a) the Senior Percentage of the Scheduled Principal Balance of such Mortgage Loan, and (b) either (A) the Senior Prepayment Percentage, or (B) if an Excess Loss was sustained with respect to such Liquidated Loan during such prior calendar month, the Senior Percentage of the amount of the Liquidation Proceeds allocable to principal received with respect to such Mortgage Loan, (iii) the Senior Prepayment Percentage of the sum of (a) all Principal Prepayments in Full of Mortgage Loans in such Loan Group received during the related Prepayment Period and (b) all partial Principal Prepayments of Mortgage Loans in such Loan Group and applied during the related Prepayment Period and (iv) with respect to any Distribution Date prior to the Cross-Over Date only, the Senior Prepayment Percentage of the Recoveries for such Loan Group received during the related Prepayment Period; provided, however, that, if a Bankruptcy Loss that is an Excess Loss is sustained with respect to such Mortgage Loan that is not a Liquidated Loan, the Senior Optimal Principal Amount will be reduced on the related Distribution Date by the Senior Percentage of the principal portion of such Bankruptcy Loss.

Class P Principal Amount As of the Closing Date, $100.

PO Principal Amount As to any Distribution Date and Loan Group, the sum of the applicable PO Percentage of (a) the principal portion of each Monthly Payment due on each Mortgage Loan in such Loan Group on the related Due Date, (b) the Stated Principal Balance, as of the date of repurchase, of each Mortgage Loan in such Loan Group that was repurchased by the Depositor pursuant to this Agreement as of such Distribution Date, (c) any Substitution Adjustment Amount in connection with any Defective Mortgage Loan in such Loan Group received with respect to such Distribution Date, (d) any Liquidation Proceeds allocable to recoveries of principal of Mortgage Loans in such Loan Group that are not yet Liquidated Mortgage Loans received during the calendar month preceding the month of such Distribution Date, (e) with respect to each Mortgage Loan in such Loan Group that became a Liquidated Mortgage Loan during the calendar month preceding the month of such Distribution Date, the amount of Liquidation Proceeds (excluding Excess Proceeds) allocable to principal received with respect to such Mortgage Loan during the calendar month preceding the month of such Distribution Date with respect to such Mortgage Loan and (f) all Principal Prepayments received on the Mortgage Loans in such Loan Group received during the calendar month preceding the month of such Distribution Date.

Class Principal Amount With respect to each Class of Certificates, the aggregate of the Certificate Principal Amounts of all Certificates of such Class at the date of determination. With respect to any Lower-Tier Interest, the initial Class Principal Amount as shown or described in the table set forth in the Preliminary Statement for the issuing REMIC, as reduced by principal distributed with respect to such Lower-Tier Interest and Realized Losses allocated to such Lower-Tier Interest at the date of determination.

Initial Principal Amount means, with respect to any Series or Class (or Subclass) of Notes, the aggregate initial principal amount of such Series or Class (or Subclass) of Notes specified in the applicable Series Supplement.

Notional Principal Amount For calculating interest payments, on each Class of outstanding Interest Only MAC Notes as of any Payment Date, an amount equal to the outstanding Class Principal Balance as of such Payment Date of the portion of the related Class of Class M Notes that was exchanged for such Interest Only MAC Note.

Subordinated Optimal Principal Amount With respect to each Mortgage Pool and each Distribution Date, an amount equal to the sum of the following (but in no event greater than the aggregate Class Certificate Balances of the Subordinated Certificates immediately prior to such Distribution Date):

PO Formula Principal Amount As to any Distribution Date, the sum of the applicable PO Percentage of (a) the principal portion of each Scheduled Payment (without giving effect, prior to the Bankruptcy Coverage Termination Date, to any reductions thereof caused by any Debt Service Reductions or Deficient Valuations) due on each Mortgage Loan on the related Due Date, (b) the Stated Principal Balance of each Mortgage Loan that was repurchased by the Seller or the Master Servicer pursuant to this Agreement as of such Distribution Date, (c) the Substitution Adjustment Amount in connection with any Deleted Mortgage Loan received with respect to such Distribution Date, (d) any Insurance Proceeds or Liquidation Proceeds allocable to recoveries of principal of Mortgage Loans that are not yet Liquidated Mortgage Loans received during the calendar month preceding the month of such Distribution Date, (e) with respect to each Mortgage Loan that became a Liquidated Mortgage Loan during the month preceding the calendar month of such Distribution Date, the amount of Liquidation Proceeds allocable to principal received during the month preceding the month of such Distribution Date with respect to such Mortgage Loan and (f) all Principal Prepayments received during the related Prepayment Period.

Non-PO Principal Amount As to any Distribution Date and Loan Group, the sum of (i) the sum of the applicable Non-PO Percentage of (a) the principal portion of each Monthly Payment due on each Mortgage Loan in such Loan Group on the related Due Date, (b) the Stated Principal Balance, as of the date of repurchase, of each Mortgage Loan in such Loan Group that was repurchased by the Depositor pursuant to this Agreement as of such Distribution Date, (c) any Substitution Adjustment Amount in connection with a Defective Mortgage Loan in such Loan Group received with respect to such Distribution Date, (d) any Liquidation Proceeds allocable to recoveries of principal of Mortgage Loans in such Loan Group that are not yet Liquidated Mortgage Loans received during the calendar month preceding the month of such Distribution Date, (e) with respect to each Mortgage Loan in such Loan Group that became a Liquidated Mortgage Loan during the calendar month preceding the month of such Distribution Date, the amount of Liquidation Proceeds (excluding Excess Proceeds) allocable to principal received with respect to such Mortgage Loan during the calendar month preceding the month of such Distribution Date and (f) all Principal Prepayments on the Mortgage Loans in such Loan Group received during the calendar month preceding the month of such Distribution Date; and (ii) the Non-PO Recovery for such Distribution Date.

Class A Non-PO Optimal Amount As to any Distribution Date, the sum for such Distribution Date of (i) the Class A Interest Accrual Amount, (ii) the Aggregate Class A Unpaid Interest Shortfall and (iii) the Class A Non-PO Optimal Principal Amount.

Current Principal Amount With respect to any Certificate as of any Distribution Date, the initial principal amount of such Certificate, and reduced by (i) all amounts distributed on previous Distribution Dates on such Certificate with respect to principal, (ii) the principal portion of all Realized Losses allocated prior to such Distribution Date to such Certificate, taking account of the Loss Allocation Limitation and (iii) in the case of a Subordinate Certificate, such Certificate's pro rata share, if any, of the applicable Subordinate Certificate Writedown Amount for previous Distribution Dates. With respect to any Class of Certificates, the Current Principal Amount thereof will equal the sum of the Current Principal Amounts of all Certificates in such Class. Notwithstanding the foregoing, solely for purposes of giving consents, directions, waivers, approvals, requests and notices, the Class R-I and Class R-II Certificates after the Distribution Date on which they each receive the distribution of the last dollar of their respective original principal amount shall be deemed to have Current Principal Amounts equal to their respective Current Principal Amounts on the day immediately preceding such Distribution Date.

Original Principal Amount means $270,000,000 for the Class A-1 Notes, $200,000,000 for the Class A-2a Notes, $290,000,000 for the Class A-2b Notes, $410,000,000 for the Class A-3 Notes and $132,710,000 for the Class A-4 Notes.

Subordinate Optimal Principal Amount For any Distribution Date and any Loan Group, the sum for each Mortgage Loan in such Loan Group of (i) the Subordinate Percentage of (a) the principal portion of each Scheduled Payment (without giving effect, prior to the Bankruptcy Coverage Termination Date, to any reductions thereof caused by any Debt Service Reductions or Deficient Valuations) due on each such Mortgage Loan on the related Due Date, (b) the principal portion of the Purchase Price of each such Mortgage Loan to the extent it was repurchased by the Transferor pursuant to this Agreement as of such Distribution Date, (c) the Substitution Adjustment Amount in connection with any Deleted Mortgage Loan related to such Loan Group received with respect to such Distribution Date, (d) any Liquidation Proceeds (including Insurance Proceeds) allocable to recoveries of principal of Mortgage Loans related to such Loan Group that are not yet Liquidated Loans, received during the calendar month preceding the month of such Distribution Date, (ii) with respect to each Mortgage Loan in such Loan Group that became a Liquidated Loan during the calendar month preceding the month of such Distribution Date, the portion of the amount of the Liquidation Proceeds allocable to principal received with respect to such Mortgage Loan that was not included in clause (ii) of the definition of "Senior Optimal Principal Amount" for such Distribution Date, (iii) the Subordinate Prepayment Percentage of the sum of (a) all Principal Prepayments in Full of Mortgage Loans in such Loan Group received during the related Prepayment Period and (b) all partial Principal Prepayments of Mortgage Loans in such Loan Group and applied during the related Prepayment Period and (iv) with respect to any Distribution Date prior to the Cross-Over Date only, the Subordinate Prepayment Percentage related to such Group of the Recoveries received during the related Prepayment Period; provided, however, that if a Bankruptcy Loss that is an Excess Loss is sustained with respect to a Mortgage Loan in such Loan Group that is not a Liquidated Loan, the Subordinate Optimal Principal Amount will be reduced on the related Distribution Date by the Subordinate Percentage of the principal portion of such Bankruptcy Loss.

Collateral Principal Amount As of any date of determination, the sum of (a) the Aggregate Principal Balance of the Collateral Obligations (other than Defaulted Obligations except as otherwise expressly set forth herein) and (b) without duplication, the amounts on deposit in any Account (including Eligible Investments therein) representing Principal Proceeds; provided that for purposes of calculating the Concentration Limitations and the CCC Excess, Defaulted Obligations shall be included in the Collateral Principal Amount with a principal balance equal to the Defaulted Obligation Balance thereof.

Non-PO Formula Principal Amount As to any Distribution Date, the sum of (i) the sum of the applicable Non-PO Percentage of (a) all monthly payments of principal due on each Mortgage Loan on the related Due Date, (b) the principal portion of the purchase price of each Mortgage Loan that was repurchased by the Seller pursuant to this Agreement as of such Distribution Date, excluding any Mortgage Loan that was repurchased due to a modification of the Mortgage Rate, (c) the Substitution Adjustment Amount in connection with any Deleted Mortgage Loan received with respect to such Distribution Date, (d) any Insurance Proceeds or Liquidation Proceeds allocable to recoveries of principal of Mortgage Loans that are not yet Liquidated Mortgage Loans received during the calendar month preceding the month of such Distribution Date, (e) with respect to each Mortgage Loan that became a Liquidated Mortgage Loan during the calendar month preceding the month of such Distribution Date, the amount of Liquidation Proceeds allocable to principal received with respect to such Mortgage Loan, and (f) all partial and full Principal Prepayments received during the related Prepayment Period and (ii) (A) any Subsequent Recoveries received during the calendar month preceding the month of such Distribution Date, or (B) with respect to Subsequent Recoveries attributable to a Discount Mortgage Loan that incurred (1) an Excess Loss or (2) a Realized Loss after the Senior Credit Support Depletion Date, the Non-PO Percentage of any Subsequent Recoveries received during the calendar month preceding the month of such Distribution Date.

Aggregate Principal Amount means, as of any date of calculation, the principal amount or Accreted Value of the Bonds referred to.

Lower-Tier Principal Amount As described in the Preliminary Statement.

Class A Principal Allocation Percentage With respect to any Distribution Date, the percentage equivalent of a fraction, determined as follows: (A) with respect to the Group I Class A Certificates, a fraction, the numerator of which is (x) the portion of the Principal Remittance Amount for such Distribution Date that is attributable to the principal received or advanced on the Group I Mortgage Loans and the denominator of which is (y) the Principal Remittance Amount for such Distribution Date and (B) with respect to the Group II Class A Certificates, a fraction, the numerator of which is (x) the portion of the Principal Remittance Amount for such Distribution Date that is attributable to the principal received or advanced on the Group II Mortgage Loans and the denominator of which is (y) the Principal Remittance Amount for such Distribution Date.