Evidence of the expiration of government incentives for home buyers surfaced prominently in the S&P/Case-Shiller Home Price Indices for August, which broke their recent trend of sequential price increases during the month as sellers cut prices to make up for the lost tax credits.

The 10-City Composite Index was down 0.1% from July; the 20-City down 0.2%, as only five markets posted month-to-month gains. Year over year, the 10 City was up 2.6% and the 20-City Composite was up 1.7%, but 12 of the 20 markets were down compared to August, 2009.

"A disappointing report," said David M. Blitzer, chairman of the index committee at S&P. "Home prices broadly declined in August...Over the last four months both the 10- and 20-City Composites show slowing growth, after sustaining consistent gains since their April 2009 troughs."

He added, "Indeed, the housing market appears to have stabilized at new lows. At this time, it does not seem that any of the markets are hanging on to the temporary momentum caused by the homebuyers' tax credits."

Among the five markets to post month-to-month gains were Detroit (+0.5%) and Las Vegas (+0.1%), which, with indices of 71.54 and 101.03, arguably could not get any lower. Likewise, Chicago, wit and index of 126.70, posted a 0.4% gain. The other two gainers were New York, where the index of 175.27 is catching up to longtime No. 2 Los Angeles (175.55), with a +0.2% rise; and Washington D.C., which remains the nation's strongest market in terms of price appreciation since January, 2000 with an index of 188.26, up 0.3% from July.

Among the rest of the markets, Phoenix took the biggest hit, with a 1.3% decline from July to an index of 108.84, still 0.4% ahead of August last year. Atlanta remained with Phoenix, Detroit, Las Vegas and Cleveland in the under-110 index group with a 109.09, down 0.8% from July and down 2% year-over year.

The strongest markets remain those in California in addition to Washington and New York. Los Angeles was down 0.4% on the month-to-month scale but remained up 5.4% year-over-year; San Francisco was down 0.3% but up 7.8%, respectively; San Diego was down 0.6% but up 6.9%, respectively.

Among the other markets still holding onto year-over-year gains were Boston (158.35), which was down 0.3% from July but remained up 1.5% from August, 2009; Minneapolis (126.53), which was off 0.3% sequentially but up 2.9% on an annual comparison.

The Florida markets remained down, with Miami (147.47) off 0.3% on the month and down 1% from August, 2009 and Tampa (137.53) down 0.5% and 4.1% respectively. Charlotte (116.60) was down 0.4% and 3.4%, respectively.Dallas (119.41) was down 1.1% and 1.7%, respectively, and Denver (128.57) down 0.1% and 1.7%. Seattle fell 0.8% and 2.4%; Portland fell 0.9% and 2.3%.

Las Vegas again posted the largest year-over-year decline of 4.5%.

Learn more about markets featured in this article: Los Angeles, CA.