U.S. home price decline slows to 2.6%, Case Shiller says Home prices in 20 major U.S. cities are down 2.6% in March compared to a year earlier, according to the Case Shiller index. Irfan Khan / Los Angeles Times / May 29, 2012 May 29, 2012, 7:15 a.m. Home prices in 20 American cities slumped in March compared to a year earlier, but the slide was the slowest since December 2010. The S&P Case Shiller index of property values fell 2.6% after falling 3.5% in February. Nationwide, however, prices were up month over month - the first two-month streak since a tax credit for home-buyers expired in spring 2010. The data signals a potential turnaround in the housing market, or, at the very least, signs of stabilization, analysts believe. Home values in thirteen of the 20 cities showed year-over-year declines. Atlanta, which along with Chicago, Las Vegas, New York and Portland, Ore., reached new lows, suffered an 18% plunge. Phoenix had the most substantial increase, with prices rising 6.1%. In California, values slid 4.8% in Los Angeles, nearly 3% in San Francisco and 2.7% in San Diego. The index, created by economists Karl E. Case and Robert J. Shiller, is widely considered the most reliable read on home values. The housing index compares the latest sales of detached houses with previous sales and accounts for factors such as remodeling that might affect a house's sale price over time. Las Vegas housing market improves in April Zillow: 31.4% of U.S. homeowners are underwater on mortgages