The promise made by a mortgage company in San Diego could not have been more blunt. “Accredited Home Lenders offers an unusually broad line of subprime mortgage products for wholesale mortgage brokers,” the company’s Web site boasted in its heyday. “Send us your toughest loans, and let us earn your business.” Those were the days: from 2005 to 2007, Accredited made $29 billion in subprime loans. Among them was a balloon mortgage for $384,000 in November 2005 to one Domingo Cedano, who used the money to buy a three-family building at 2321 Prospect Avenue in the Bronx. The mortgage carried an interest rate of 7 3/8 and monthly payments of $2,491. Mr. Cedano put none of his own money into the purchase.