For the week ending Sept. 13, the MBA's market composite index, a measure of mortgage loan application volume, edged down 0.1 percent from a week earlier.
"The jump in U.S. Treasury rates at the end of last week caused mortgage rates to increase across the board, with the 30-year fixed-rate mortgage climbing to 4.01 percent -- the highest in seven weeks," said Joel Kan, the MBA's associate vice president of economic and industry forecasting.
"Refinancing activity dropped as a result, driven solely by conventional refinances," said Kan.
The refinance index, which measures the activity to replace higher rate mortgages with lower rate mortgages, dropped 4 percent from the previous week, according to the MBA.
The MBA's purchase index before seasonal adjustment increased 16 percent from the previous week. After removing the influences of predictable seasonal patterns, the seasonally adjusted purchase index increased 6 percent from a week earlier, according to the MBA.
"The purchase index increased for the third straight week to its highest reading since July. Additionally, the average loan amount on purchase applications increased to its highest level since June," Kan added.