amount of each Class is outstanding at all times, regardless of any exchanges that may occur. •   Based on the Class Factors published in the preceding and current months (and Interest Rates), investors in any Class (other than an Accrual Class) can calculate the amount of principal and interest to be distributed to that Class, and investors in an Accrual Class can calculate the total amount of principal to be distributed to (or interest to be added to the Class Principal Balance of) that Class on the Distribution Date in the current month. •   Investors may obtain current Class Factors on e-Access. See "Description of the Securities – Distributions" in the Base Offering Circular. Termination The Trustee, at its option, may purchase or cause the sale of the Trust Assets and thereby terminate the Trust on any Distribution Date on which the aggregate of the Class Principal Balances of the Securities is less than 1% of the aggregate Original Class Principal Balances of the Securities. The Trustee will terminate the Trust and retire the Securities on any Distribution Date upon the Trustee's determination that the REMIC status of either Trust REMIC has been lost or that a substantial risk exists that this status will be lost for the then current taxable year. Upon any termination of the Trust, the Holder of any outstanding Security (other than a Residual or Notional Class Security) will be entitled to receive that Holder's allocable share of the Class Principal Balance of that Class plus any accrued and unpaid interest thereon at the applicable Interest Rate, and any Holder of any outstanding Notional Class Security will be entitled to receive that Holder's allocable share of any accrued and unpaid interest thereon at the applicable Interest Rate. The Residual Holders will be entitled to their pro rata share of any assets remaining in the Trust REMICs after payment in full of the amounts described in the foregoing sentence. However, any remaining assets are not likely to be significant. Modification and Exchange All or a portion of the Classes of REMIC Securities specified on the front cover of this Supplement may be exchanged for a proportionate interest in the related MX Class shown on Schedule I to this Supplement. Similarly, all or a portion of the related MX Class may be exchanged for proportionate interests in the related Classes of REMIC Securities. This process may occur repeatedly. Each exchange may be effected only in proportions that result in the principal and interest entitlements  of  the  Securities  received  being  equal  to  the  entitlements  of  the  Securities surrendered. A Beneficial Owner proposing to effect an exchange must notify the Trustee through the Beneficial Owner's Book-Entry Depository participant. This notice must be received by the Trustee not later than two Business Days before the proposed exchange date. The exchange date can be any Business Day other than the last Business Day of the month. The notice must contain the outstanding principal balance of the Securities to be included in the exchange and the proposed exchange date. The notice is required to be delivered to the Trustee in writing at its Corporate Trust Office at Wells Fargo Bank, N.A., 45 Broadway, 12th Floor, New York, New York 10006, Attention: Ginnie Mae REMIC Program Agency Group 2007-057. The Trustee may be contacted by telephone at (212) 515-5262 and by fax at (212) 509-1042. S-13