Mortgage applications increased 4% from a week ago on a seasonally adjusted basis for the week ended Jan. 20, the Mortgage Bankers Association reported, citing its latest weekly mortgage application survey.

The association noted that the week's results included an adjustment for the Martin Luther King Jr. Day holiday.

The market composite index, which measures mortgage application volume, decreased 5% on an unadjusted basis compared to the previous week.

The seasonally adjusted purchase index increased 6% week over week to reach its highest level since June 2016. The unadjusted purchase index rose 2% compared to the previous week and was 0.1% higher than the year-ago level for the same week.

The refinance index inched up 0.2% from the previous week.

The refinance share of mortgage activity decreased to 50% of total applications from 53.0% in the previous week, marking the lowest level since July 2015. Adjustable-rate mortgage activity comprised 5.7% of total applications, remaining unchanged from the previous week.