US mortgage applications increased for the second week in a row, according to the Mortgage Bankers Association.

The seasonally adjusted index of mortgage application activity increased 1.4% last week to 561.2. This marks the highest level in 11 weeks.

The seasonally adjusted refinancing index jumped 4.6% to 1,640.8 -- the highest level since the end of March.

The share of refinancings among total loan applications was 39.6% for the week ended Aug. 11, up from 38% the week prior.

The seasonally adjusted purchase mortgage index fell last week by 0.8% to 385.9. The purchase index is still well below last year's level of 499.3.

Many borrowers have turned to ARMs in recent years, but with rates on fixed-rate mortgages dropping, consumers have begun refinancing out of ARMs into fixed-rate products.

The ARM share of activity fell to 27.2% of total mortgage application. This is the lowest point since February 2004.

The average rate on a 30-year fixed-rate mortgage was 6.54% for the week, up from 6.45 the week prior. Fifteen-year fixed rate mortgages averaged 6.15%, up from 6.10%. One-year ARMs also saw an increase, up to 5.97%.

The MBA's survey covers 50% of all US retail residential mortgage loans. Respondents include mortgage bankers, commercial banks and thrifts.