U.S. mortgage originations in the third quarter fell 9 percent from the prior period as fewer borrowers refinanced, according to estimates from Inside Mortgage Finance publisher Guy Cecala.

Banks and other mortgage companies lent about $500 billion for home loans in the quarter, down from $550 billion, Cecala said Friday. The estimate is based on data from government mortgage agencies Freddie Mac and Fannie Mae, and expectations of Federal Housing Administration, Department of Veteran Affairs and company reports.

A drop in refinance activity is likely to hit Fannie Mae and Freddie Mac the hardest because the agencies handle the majority of refinanced loans, said Cecala, whose Bethesda, Md.-based publication has been tracking mortgage data for 25 years. Thirty-year mortgage rates fell to 4.61 percent at the end of March, fueling a refinancing boom in the second quarter.

"Rates have been low this year so most people who could refinance have already refinanced," Cecala said. "Overall the outlook is not good for refinance activity."

Sales of home loans by mortgage lenders to Freddie Mac declined 19 percent to $122 billion in the third quarter from $150 billion in the prior period, Cecala said. Sales to Fannie Mae declined 37 percent, he said.

Bank of America Corp., the second-biggest U.S. home lender, picked up market share on leader Wells Fargo & Co. in the quarter, Cecala said. Bank of America's lending totaled 20.5 percent of all mortgage loans in the first half, compared with Wells Fargo's 23.5 percent, Inside Mortgage Finance said.