Bay Area home sales jumped 10 percent last month, the best January sales level in five years.

Buyers in the nine-county region purchased 5,479 new and resold houses and condominiums last month, real estate information service DataQuick reported Thursday.

In contrast, the California Association of Realtors on Wednesday reported a 4 percent increase in Bay Area single-family home sales last month.

DataQuick attributed the jump in sales to lower prices, "ultra-low" interest rates, a modestly improving economy and a record number of investor purchases.

Absentee buyers — mostly investors — last month purchased a record 25 percent of all Bay Area homes sold, up from nearly 23 percent a year earlier.

The median price declined to $326,000, down 3 percent from December and nearly 4 percent from a year ago.

DataQuick president John Walsh suggested the winter typically produces fewer sales and last month's purchases were skewed toward distressed, lower-cost properties.