The S&P/Case-Shiller U.S. National Home Price Index posted its largest year-to-year quarterly decline in the second quarter of 2008, but prices in nine of the 20 measured markets posted increases from May to June, S&P announced Tuesday morning.

The 10-City Composite Index has now fallen 20.3% and the 20-City Index has dropped 18.8% from their peaks, which S&P said was reached in the summer of 2006.

The national HPI registered 15.4% drop from second quarter 2007 to the same period this year. The year-over-year decline for the first quarter was 14.2%. It now stands at 155.32 compared to a base index of 100 set in January of 2000.

The 10-City Composite was down 17% year-over-year, a record drop, and the 20-City Composite fell 15.9%, also a record. That compares with 16.9% and 15.8% year-over-year declines for the first quarter, which S&P took as evidence that the acceleration in decline "was only moderate" in June.

"While there is no national turnaround in residential real estate prices, it is possible that we are seeing some regions struggling to come back, which has resulted in some moderation in price declines at the national level," said David M. Blitzer, chairman of the Index Committee at S&P. "Depending on where you focus on the details of the report, you can see some different stories on where home prices are headed."

He added, "The rate of home price decline may be slowing. For the month, the 10-City Composite was down 0.6% and the 20-City Composite was down 0.5%. While still falling, these are far less than the 2-2.5% monthly drops seen earlier in 2008."

Month-to-month, nine markets reported price increases from May to June, including Atlanta (+0.6%), Boston (+1.2%), Charlotte (+0.4%), Chicago (+0.2%), Cleveland (+0.7%), Dallas (+0.7%), Denver (+1.5%), Minneapolis (+1%), and New York (+0.2%). Still, all of those markets remain down year-over-year, with Atlanta at -8.1%, Boston -5.2%, Charlotte -1%, Chicago -9.5%, Cleveland -7.3%, Dallas -3.2%, Denver -4.7%, Minneapolis -13.9%, and New York -7.3%.

Denver and Boston have now posted three consecutive months of increases; Dallas and Charlotte have logged four.

Phoenix posted the steepest month-to-month drop, -2.6%, putting it down 27.9% from June of 2007. Las Vegas and Miami continued as the markets with the largest declines year-over-year at -28.6% and - 28.3% respectively, and both markets continued to see price erosion in June, with prices off 1.6% and 1.7% respectively.

California markets continued their plunge, with Los Angeles down 1.4% month-to-month and 25.3% year-over-year; San Diego at -1.5% and -24.2% respectively, and San Fransciso at -1.8% and -23.7%. Likewise in Florida, where the only market other than Miami measured by the Case-Shiller Index, Tampa, is off 1.1% month-to-month and 20.1% year-over-year.

The Washington D.C. market was down 0.9% month-to-month and down 15.7% year-over-year. Detroit was off another 0.1% for June and 16.3% compared to last year. Seattle was down 0.2% and down 7.1% respectively, and Portland was down 0.3% and down 5.8% respectively.

In releasing the data, S&P said, "Although there are some improving regional numbers, the picture of the overall residential real estate market remains weak."

Separately, the Office of Federal Housing Enterprise Oversight released data for the second quarter that appears to confirm the S&P/Case-Shiller notion of decelerating rates of price decline. OFHEO, which tracks only homes covered by loans that conform to Fannie Mae, Freddie Mac and Federal Housing Administration standards, reported that its purchase-only House Price Index slipped 1.4% from the first to the second quarter after falling 1.7% in the first quarter.

OFHEO said its year-over-year data showed a 4.8% decrease in home prices.That decline is the largest in the purchase-only index¹s 17-year history.OFHEO¹s all-transactions index fell 1.4% in the latest quarter and was down1.7 percent over the four-quarter period.

"Tighter credit conditions and relatively high inventory levels led to some sharp price declines in the second quarter," said OFHEO Director James B.Lockhart. "However, the majority of Metropolitan Statistical Areas posted positive four-quarter growth."

Many of those MSAs, however, were passed over during the housing boom and did not experience the price appreciation seen in the big metro areas. The OFEHO data also reflects sales of lower-end homes, those that fell under the maximum loan limits of $417,000. Those limits will rise to a maximum of $729,750, which will vary among metro areas.

OFHEO acknowledged the discrepancy between its numbers and the Case-Shiller index in its quarterly report. It concluded that the difference "could be attributed to relative price weakness for homes that did not have Enterprise financing."

"OFHEO has assembled sales transaction data and mortgage information from a variety of different sources and has used it to estimate recent price trends for homes with different financing and borrower characteristics," the report stated. "The analysis, which focuses on price trends in central California and other parts of that state, finds that homes with the riskiest mortgages have seen much greater price declines in recent quarters. For example, since prices peaked in central California, prices have fallen about 30.7% for homes whose owners had the highest debt-to-income (DTI) ratios. By contrast, in the same area, prices have fallen about 22.9% for homes with low-DTI mortgages."

OFHEO announced that it would include transactions under the higher conforming loan limits. Explaining its decision, OFHEO stated, "Under the Recovery Rebates and Economic Stimulus for the American People Act of 2008, Fannie Mae and Freddie Mac are temporarily allowed to buy mortgages in certain high-cost areas with loan amounts in excess of the normal loan limit ($417,000 for homes in the continental United States). OFHEO has considered whether house price data from these higher-balance ³temporary jumbo conforming² mortgages will be used and, if so, whether they would be later removed from the sample when the temporary limits expire in January 2009.After considering various options, OFHEO has decided to include these data when it calculates the HPI. The data were included in the estimation of first quarter 2008 HPI figures released in May. The impact of those data on the HPI has been quite small so far."

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