The number of Americans filing mortgage applications soared 11.1% for the week ending Sept. 7 as interest rates continued to drop,  an industry trade group said.

The Mortgage Bankers Association believes the steep rise in refinance applications for the week may overstate the actual increase because some lenders work solely online. And with many homeowners having an extra day off, it's possible they turned to online or direct origination channels to fill out applications during the holiday period. Lenders with retail offices, on the other hand, witnessed drops in applications. 

The adjusted refinance index grew 12% from the previous week, while the purchase index jumped 8%.

The refinance share of all mortgage activity also edged up to 80% of applications from 70% a week earlier.

The average, 30-year, fixed-rate mortgage with a conforming loan balance fell to 3.75% from 3.78%. In addition, the 30-year, FRM jumbo loan rate declined to 4% from 4.05%.

Meanwhile, the average 30-year, FRM backed by FHA declined to 3.50% from 3.54%, a new low for the MBA survey.

The 15-year, FRM also fell to 3.07% from 3.10%, and the 5/1 ARM hit 2.63%, slightly down from last week.

kpanchuk@housingwire.com