Home prices nationwide appear to have reached a seasonal trough in February, after falling to the lowest level since March 2003. The RadarLogic RPX Composite index, which tracks home prices in 25 metropolitan areas, fell to $178.12 per square foot, down 4.3% compared to February 2010 and down 36% from the index's all time high in June 2007. RadarLogic said that both supply and demand factors in the housing market are contributing to price depreciation. "The foreclosure process remains bogged down after investigations launched late last year prompted temporary halts by some mortgage servicers and created a bottleneck as paperwork was re-filed," the report said. "Housing demand is also constrained." March existing home sales posted 3.7% above February sales, yet 6.3% below sales in March 2010, according to the National Association of Realtors. On a regional basis, the largest declines in home price occurred in the South, according to RadarLogic, down 4.3% compared to January and down 9.7% compared to the year ago period. In Atlanta prices plummeted 16.3% compared to 2010. Prices fell 13.6% in Jacksonville, Fla. and 13.1% in Miami. RadarLogic mentioned that more home purchases are being made by corporate investors and all-cash buyers. Recent data suggest this trend will continue, the research firm said, as these purchases "have tended to be at large discounts." Write to Christine Ricciardi. Follow her on Twitter @HWnewbieCR.