FORM OF MORTGAGE LOAN PURCHASE AGREEMENT

This Mortgage Loan Purchase Agreement (the "Agreement") dated as of April 1, 2007 is between CitiMortgage, Inc. ("CMI" or the "Seller") and Citicorp Mortgage Securities, Inc., a Delaware corporation ("CMSI"). The Seller agrees to sell, and CMSI agrees to purchase, the mortgage loans originated or acquired by CMI as described and set forth in the Mortgage Loan Schedule attached as exhibit B (the "mortgage loans") to the Pooling and Servicing Agreement dated as of April 1, 2007 (the "Pooling Agreement"), between CMSI, CMI, U.S. Bank National Association, a national banking association, in its individual capacity and as Trustee (the "Trustee"), and Citibank, N.A., in its individual capacity and as Paying Agent, Certificate Registrar and Authentication Agent, relating to the issuance of CMALT (CitiMortgage Alternative Loan Trust), Series 2007-A4 REMIC Pass-Through Certificates class A, class B and residual certificates. Terms used without definition herein shall have the respective meanings assigned to them in the Pooling Agreement or, if not defined therein, in the Senior Underwriting Agreement dated March 27, 2007 among CMSI, Citigroup Inc. and Morgan Stanley & Co. Incorporated (the "Senior Underwriter") (the "Senior Underwriting Agreement") and in the Subordinated Underwriting Agreement dated April 19, 2007 among CMSI, Citigroup Inc. and Greenwich Capital Markets, Inc (the "Subordinated Underwriter" and, together with the Senior Underwriter, the "Underwriters") (the "Subordinated Underwriting Agreement" and, together with the Senior Underwriting Agreement, the "Underwriting Agreements").

1.   Purchase Price . The purchase price (the "Purchase Price") for the mortgage loans shall consist of (a) cash in the amount of _____________% of the aggregate scheduled principal balance thereof as of the cut-off date, plus accrued interest thereon at the rate of 6.00% per annum on the mortgage loans in pool I and 5.50% per annum on the mortgage loans in pool II, from and including the cut-off date to but excluding the closing date, (b) the class IA-IO and IIA-IO certificates, (c) the class LR certificates and (d) the class PR certificates. Such cash shall be payable by CMSI to the Seller on the closing date in same-day funds, and the Seller will receive on the closing date: (a) the class IA-IO and IIA-IO certificates and (b) the class LR and class PR certificates evidencing the residual interests in the lower-tier REMIC and the pooling REMIC, respectively. If CMSI for any reason shall repay to any Underwriter any portion of the price paid to CMSI by any Underwriter pursuant to the Underwriting Agreements, the Seller shall simultaneously and in the same manner repay to CMSI a proportionate amount of the Purchase Price as such repayment to any Underwriter.

Upon payment of the Purchase Price, the Seller shall transfer, assign, set over and otherwise convey to CMSI without recourse all of the Seller's right, title and interest in and to the mortgage loans, including all interest and principal received or receivable by the Seller on or with respect to the mortgage loans (other than payments of principal and interest due and payable on the mortgage loans on or before the cut-off date and prepayments of principal on the mortgage loans received or posted prior to the close of business on the cut-off date), together with all of the Seller's right, title and interest in and to the proceeds of any related title, hazard or other insurance policies and Primary Mortgage Insurance Certificates. The Seller agrees to deliver to CMSI all documents, instruments and agreements required to be delivered by CMSI to the Trustee under the Pooling Agreement and such other documents, instruments and agreements as CMSI shall reasonabl