Mortgage applications increased 13.9% from one week earlier, according to data from the Mortgage Bankers Association’s Weekly Mortgage Applications Survey for the week ending Sep. 18, 2015.

The previous week’s results included an adjustment for the Labor Day holiday.

The Market Composite Index, a measure of mortgage loan application volume, increased 13.9% on a seasonally adjusted basis from one week earlier. On an unadjusted basis, the Index increased 26% compared with the previous week. The Refinance Index increased 18% from the previous week. The seasonally adjusted Purchase Index increased 9% from one week earlier to its highest level since June 2015. The unadjusted Purchase Index increased 20% compared with the previous week and was 27% higher than the same week one year ago.

“We saw significant rate volatility last week surrounding the FOMC meeting, and rate declines toward the end of the week likely drove applications from both prospective home buyers and borrowers looking to refinance. The 30-year fixed rate remained unchanged over the week even though there was substantial intra-week fluctuation, but we saw rate decreases in other loan products like the 15-year fixed, 5/1 ARM, and 30-year jumbo,” said Mike Fratantoni, MBA’s Chief Economist.

The refinance share of mortgage activity increased to 58.4% of total applications from 56.2% the previous week. The adjustable-rate mortgage (ARM) share of activity increased to 6.9% of total applications.

The FHA share of total applications decreased to 12.9% from 14.2% the week prior. The VA share of total applications decreased to 10.0% from 10.7% the week prior. The USDA share of total applications decreased to 0.7% from 0.8% the week prior.

The average contract interest rate for 30-year fixed-rate mortgages with conforming loan balances ($417,000 or less) remained unchanged at 4.09%, with points increasing to 0.45 from 0.42 (including the origination fee) for 80% loan-to-value ratio (LTV) loans. The effective rate remained unchanged from last week.

The average contract interest rate for 30-year fixed-rate mortgages with jumbo loan balances (greater than $417,000) decreased to 3.99%, its lowest level since May 2015, from 4.04%, with points increasing to 0.36 from 0.26 (including the origination fee) for 80% LTV loans. The effective rate decreased from last week.

The average contract interest rate for 30-year fixed-rate mortgages backed by the FHA remained unchanged at 3.88%, with points decreasing to 0.33 from 0.35 (including the origination fee) for 80% LTV loans. The effective rate decreased from last week.

The average contract interest rate for 15-year fixed-rate mortgages decreased to 3.31% from 3.33%, with points increasing to 0.42 from 0.26 (including the origination fee) for 80% LTV loans. The effective rate increased from last week.

The average contract interest rate for 5/1 ARMs decreased to 2.95%, its lowest level since May 2015, from 3.04%, with points increasing to 0.58 from 0.36 (including the origination fee) for 80% LTV loans. The effective rate decreased from last week.