; and (5) is not guaranteed, in whole or in part, by the United States Government. 322. Standards for qualified securities (a) Standard mortgage classifications (1) Establishment of mortgage classifications The Exchange shall prescribe classifications for residential mortgages having various degrees of credit risk, ranging from a classification of mortgages having little to no credit risk to a classification of mortgages having higher credit risk. In prescribing such classifications the Exchange shall seek to allow for the pricing of credit risk, allow for the trading of securities collateralized by each classification of mortgages established pursuant to this subsection in the forward market, and maintain well-functioning liquid markets in securities collateralized by each of the classifications of mortgages established pursuant to this subsection. (2) Underwriting Criteria For each classification of mortgages established under paragraph (1), the Exchange shall establish standards for each of the following underwriting criteria: (A) Debt-to-Income Ratio The ratio of the amount of the total monthly debt of the mortgagor to the amount of the monthly income of the mortgagor. (B) Loan-to-Value Ratio The ratio of the principal obligation under the mortgage to the value of the residence subject to the mortgage, at the time of mortgage origination. (C) Credit History Information on the credit history of the mortgagor, including credit scores of the mortgagor. (D) Loan Documentation The extent of loan documentation and verification of the financial resources of the mortgagor used to qualify the mortgagor for the mortgage, including any appraisal. (E) Occupancy Whether the residence subject to the mortgage is occupied by the mortgagor. (F) Credit Enhancement Whether any mortgage insurance or other type of insurance or credit enhancement was obtained at the time of origination. (G) Loan Payment Terms (i) In general The terms of the mortgage that determine the magnitude and timing of payments due from the mortgagor,