Single-family home prices notched their fourth straight month of increases in July, moving up 0.9% across the 20 major markets measured by the S&P/Case-Shiller Home Prices Indices released Tuesday morning.

The 10- and 20-City Composite Indices were each up 0.9% in July over June, with 17 of the 20 MSAs recording positive monthly increases. Year-over-year, however, the 10-City Composite was down 3.7% and the 20-City down 4.1%.

At the end of July, the 10-City Index stood at 156.23, the 20-City at 142.77. The baseline index of 100 is based on home prices in January, 2000.

"With July's data we are seeing not only anticipated monthly increases, but some fairly broad improvement in the annual rates of change in home prices,"said David M. Blitzer, chairman of the Index Committee at S&P Indices."This is still a seasonal period of stronger demand for houses, so monthly price increases are expected and were seen in 17 of the 20 cities. The exceptions were Las Vegas and Phoenix where prices fell, while Denver was flat. The better news is that 14 of 20 cities and both Composites saw their annual rates of change improve in July."

Blitzer stopped short of calling a rebound, however. "Other recent housing statistics show that single-family housing starts were down slightly in August, and are about 2% below their year ago level; and these levels are at 30-year lows," he said. "Existing-home sales, however, were up in August and are about 20% above their August 2010 level. The S&P/Experian Consumer Credit Default indices showed a continuing decline in mortgage default rates, a two-year trend. However, if you look at the state of the overall economy and, in particular, the recent large decline in consumer confidence, these combined statistics continue to indicate that the housing market is still bottoming and has not turned around."

The only markets not posting sequential increases were Las Vegas, with a 0.2% decline to an index of 95.48, 5.4% below last July; Denver, which was flat from June at 125.97, down 2.1% from a year earlier; and Phoenix, with a 0.1% decline to 100.54, 8.8% below July 2010.

Conversely, the only markets showing year-over-year gains were Washington, D.C., up 0.3% from last July and up 2.4% from June to 187.79, and Detroit, which rose 1.2% from a year earlier and 3.8% from June to 72.04. Detroit, however, has lost more value than any other market measured by the indicies.Washington continues as the nation's best performing market.

Among other markets showing sequential gains were Atlanta (104.55), up 0.2% from June but down 5% from last July; Boston (155.76), up 0.8% and down 1.9%, respectively; Charlotte (112.47), up 0.1% and down 3.9%; Chicago (117.78), up 1.9% and down 6.6%; Cleveland (101.53), up 0.8% and down 5.4%; Daolas (116.96), up 0.9% and down 3.2%; Los Angeles (170.05), up 0.2% and down 3.5%; Miami (141.15), up 1.2% and down 4.6%; Minneapolis (115.25), up 2.6% and down 9.1%; New York (168.51), up 1.1% and down 3.7%; Portland (135.80), up 1% and down 8.4%; San Diego (155.22), up 0.1% and down 5.9%; San Francisco (135.28), up 0.3% and down 5.6%; Seattle (135.57), up 0.1% and down 6.4%; and Tampa (129.61), up 0.8% and down 6.2%.

The Case-Shiller data has traditionally not been seasonally adjusted.Recently, S&P has also been reporting adjusted data. Seasonally adjusted, the 10-City Index was down 0.1% and the 20-City Index was flat with June, and June was flat with May for both.