A handful of nonbank mortgage companies reporting substantial losses during the fourth quarter weighed down industry-wide mortgage banking income, according to a new Inside Mortgage Trends analysis of earnings reports. A diverse group of 31 mortgage lenders that includes the biggest players in the market earned a combined $3.227 billion on their mortgage banking operations during the fourth quarter. That was down 8.2 percent from the group’s $3.516 billion during the third quarter. The fourth quarter was...[Includes one data chart]