Mortgage applications increased 16.6 percent during the first week of January, according to a weekly mortgage applications survey conducted by the Mortgage Bankers Association. The Market Composite Index, a measure of mortgage loan application volume, was 671.1, up from 575.6 one week earlier. On an unadjusted basis, the index increased 33.2 percent compared with the previous week and was up 12 percent compared with the same week one year earlier, according to the association. The refinance share of mortgage activity increased to 48.4 percent of total applications from 48.1 percent the previous week, the MBA said. The adjustable-rate mortgage (ARM) share of activity decreased to 20.1 from 20.4 percent of total applications from the previous week, moving ARM share to its lowest level since July 2003. Increases were observed for all subindexes within the market composite. The Refinance Index, a measure of refinancing application volume, increased by 17.3 percent to 1923.8 from 1640.4 the previous week and the seasonally adjusted Purchase Index increased by 16.2 percent to 472.8 from 406.9 one week earlier. Also, the seasonally adjusted Conventional Index increased by 16.8 percent to 1001.5 from 857.3 the previous week, and the seasonally adjusted Government Index increased 13.5 percent to 120.4 from 106.1 the previous week. The four-week moving average for the seasonally adjusted Market Index is down 2 percent to 612.5 from 625.1. The four week moving average is up 0.5 percent to 426.6 from 424.4 for the Purchase Index, while this average is down 5.1 percent to 1784.4 from 1879.6 for the Refinance Index.