A relatively small number of mortgage lenders helped drive the GSEs’ record-breaking mortgage business in the first half of 2003, a new Inside The GSEs analysis reveals. In fact, each of the GSEs’ top 10 customers delivered more than half of their total mortgage purchases during the first six months of the year. And in the case of the Federal Home Loan Banks, a whopping 76.9 percent of their total $46.3 billion in mortgage