In January 2005, 508 residential units were sold in Loudoun County for an average sales price of $469,168; a house remained on the market for an average of 31 days, according to the Dulles Area Association of Realtors. The Federal Home Loan Mortgage Corporation and the Federal National Mortgage Association purchase only conforming mortgages, which meet the underwriting standards established by these agencies for being in a pool of mortgages underlying a security they guarantee. Though housing flippers, people who purchased properties with the sole intention of selling them quickly to make a fast profit, comprised a part of the market in Loudoun County, it was not the majority of the foreclosures. Several mortgage products available in the market caused borrower defaults and lender foreclosures during the past year, said Stephen Cowen, director of Mortgage Production at Middleburg Mortgage. read more