According to a new study, home values in the first quarter of this year were down 7.7 percent from a year earlier.

The web site Zillow.com, which tracks home prices, says more than half of homeowners who purchased during the market peak in 2006 owe more on their mortgages than the home is worth. Zillow says the rates of negative equity run much higher in the once-hot housing markets of California, Florida, Phoenix and Las Vegas.