Mortgage activity heated up in the first week of the year, according to Mortgage Bankers' Association data, which included an adjustment for the New Year's holiday and revisions in the previous week. Purchase applications for home mortgages rose by a seasonally adjusted 5 percent in the January 5 week while applications for refinancing were up 11 percent. Unadjusted, the purchase index increased 44 percent from the prior week and was 1 percent lower than in the same week a year ago. The refinance share of mortgage activity rose 0.8 percentage points to 52.9 percent. Interest rates rose marginally, with the average interest rate on 30-year fixed-rate conforming mortgages (the conforming amount rose to $453,100 or less from $424,100 or less) up 1 basis point to 4.23 percent. The week's pickup in purchase applications points to continuation of the housing market strength seen in the last quarter.