SUPPLEMENTAL INDENTURE NO. 1 dated as of January 14, 2005 to the

                         IMPAC CMB TRUST SERIES 2004-10

                                     Issuer

                                       and

                      DEUTSCHE BANK NATIONAL TRUST COMPANY

                                Indenture Trustee




                    SUPPLEMENTAL INDENTURE NO. 1 dated as of
                             January 14, 2005 to the

                                    INDENTURE

                          Dated as of November 24, 2004





                        COLLATERALIZED ASSET-BACKED BONDS











         SUPPLEMENTAL INDENTURE NO. 1 made as of this 14th day of January 2005,
between Impac CMB Trust Series 2004-10, as issuer (the "Issuer") and Deutsche
Bank National Trust Company, as indenture trustee (the "Indenture Trustee").

                               W I T N E S S E T H


         WHEREAS, the Issuer and the Indenture Trustee entered into an Indenture
(the "Agreement") dated as of November 24, 2004, relating to the issuance of
Collateralized Asset-Backed Bonds, Series 2004-10; and

         WHEREAS, the Issuer and the Indenture Trustee desire to amend the terms
of the Agreement pursuant to and in accordance with Section 9.01(a) of the
Agreement.

         NOW, THEREFORE, in consideration of the mutual premises and agreements
herein, the Issuer and the Indenture Trustee agree as follows:

         1. Capitalized terms used herein and not defined herein shall have the
meanings assigned to such terms in the Agreement.

         2. Effective as of November 24, 2004 the Indenture is hereby amended as
follows:

         3. The eleventh sentence in the defined term BOND MARGIN under the
Appendix A Definitions to the Agreement shall be deleted in its entirety and
replaced with the following sentence: "With respect to the Class 4-A-1 Bonds, on
any Payment Date prior to the Step-Up Date, 0.370% per annum, and on any Payment
Date on and after the Step-Up Date, 0.740% per annum."

         4. Notice of this Supplemental Indenture has been given to each of
Standard & Poor's, a division of The XxXxxx-Xxxx Companies, Inc. and Xxxxx'x
Investors Service, Inc. pursuant to 9.01(a) of the Indenture.

         5. Except as amended above, the Indenture shall continue to be in full
force and effect in accordance with its terms.





3



         IN WITNESS WHEREOF, the Issuer and the Indenture Trustee have caused
their duly authorized representatives to execute and deliver this instrument as
of the date first above written.


                                   IMPAC CMB TRUST SERIES 2004-10, as
                                   Issuer Wilmington Trust Company, not in its
                                   individual capacity but solely as Owner
                                   Trustee

                                   By: /s/ Xxxxxx X. Xxxxxxx
                                       ----------------------
                                   Name:    Xxxxxx X. Xxxxxxx
                                   Title:   Financial Services Officer


                                   DEUTSCHE BANK NATIONAL TRUST COMPANY,
                                   as Indenture Trustee


                                   By: /s/ Xxxxxxx Xxxxxxxx
                                       ---------------------
                                   Name:    Xxxxxxx Xxxxxxxx
                                   Title:   Assistant Vice President