Home prices in 23 U.S. metropolitan areas fell 2.2% in December, the largest one-month drop for fiscal 2010, and a sign that foreclosed properties continue to weigh down home values across the nation, the FNC Residential Price Index revealed Monday. Mortgage technology firm FNC publishes the index to track home price levels across the nation. According to the latest report, home values fell for the seventh straight month in December. Between January of 2010 and December, home prices dropped more than 3.4%, according to the report. Of the 30 metropolitan areas surveyed, all but seven experienced price declines in December. The biggest losers were Atlanta, Chicago, Las Vegas, Orlando and Phoenix — all of which experienced double-digit declines in the last month of 2010. The big gainers were San Diego, Los Angeles and San Francisco, which experienced price jumps of at least 5% on a year-over-year basis in 2010. Significant home price declines are reflective of a burgeoning foreclosure market where distressed properties represented 26.8% of total home sales in the fourth quarter of 2010. But FNC says there’s a silver lining when considering the fact that more foreclosure sales are expected this year. “There is an upside: this trend will reduce the surplus of distressed properties and eventually bring the supply to levels in line with weak housing demand, paving ways for a more sustainable housing recovery later,” FNC said. Write to Kerri Panchuk.