(a) The mortgage loans in an insured pool shall not have loan-to-value ratios (defined as the ratio of the original principal balance of the mortgage loan to the lesser of the purchase price or original appraised value of the related security) in excess of 80 percent after giving effect to any primary policies of mortgage guaranty insurance, FHA insurance or VA guarantee.

(b) Outstanding principal balances of the mortgage loans insured, as stated in the mortgage pool policy, shall be not less than $5,000,000.

(c) The minimum number of mortgage loans insured shall be not less than 75.

(d) The mortgage loans insured shall be on one- to four-family residences and the loans, or a statistically valid random sample thereof, shall be individually underwritten. Where a random sample of mortgage loans is underwritten, the insurer's files shall document the basis for the selection of the sample utilized. No more than 10 percent of the outstanding principal balances of the mortgage loans insured as stated in the mortgage pool policy shall be on properties which, as of the date of the loan origination, the borrower did not intend to occupy as a primary or secondary residence.