Home shown for sale in Haight Ashbury neighborhood in San Francisco
A home is shown for sale in the Haight Ashbury neighborhood in San Francisco, California, August 24, 2010. REUTERS

Single-family home prices were unchanged in August, pointing to a market that continued to stabilize but has yet to gain traction, a closely watched survey said on Tuesday.

The S&P/Case Shiller composite index of 20 metropolitan areas was flat compared to the month before on a seasonally adjusted basis. A Reuters poll of economists had forecast a gain of 0.1 percent

On an unadjusted basis, price gains slowed with the index up 0.2 percent compared to a 0.9 percent gain in July.

The annual rate of decline improved, with prices in the 20 cities down 3.8 percent compared to a year over year decline of 4.1 percent the month before. Still, it fell shy of expectations for a decline of 3.5 percent in August.

The good news is continued improvement in the annual rates of change in home prices, David Blitzer, chairman of the index committee at Standard & Poor's, said in a statement.

In spring and summer's seasonally strong period for housing demand, we cautioned that monthly increases in prices had to be paired with improvement in annual rates before anyone could declare that the market might be stabilizing.

(Reporting by Leah Schnurr, Editing by Chizu Nomiyama)