The index, which maps prices in 20 key urban areas, fell 0.5 percent from October on a seasonally adjusted basis, after a 1.0 percent fall the previous month.
It was also off 1.6 percent from the year-earlier figure.All but four of the 20 metropolitan areas covered in the index fell.
Prices rose in Washington, San Diego, California; and Charlotte, North Carolina, while in hard-hit Las Vegas they were unchanged.
The five-month fall in the index represents a clear return to bearish sentiment in the market after a slow but steady rise from the May 2009 low through May 2010, according to S&P.
The seasonally adjusted index peaked in April 2006 and has since fallen in all but 13 months.
The November level was just 1.2 percent higher than the 90-month low struck in May 2009.S&P's David Blitzer said the data suggests "that a double-dip could be confirmed before spring."
Certainly (with) eight cities setting new lows, and with the only positive news concentrated in southern California and Washington DC, the data point to weakness in home prices," he said in a statement.
Economists at Barclays Capital Research said the November fall was smaller than expected.
"We expect softness to persist in the near term as home prices continue to face headwinds from the large pipeline of foreclosures entering the market," they said in a statement.
"However, we expect this to be a gradual process with some of the decline offset by increased housing demand."Inna Mufteeva, an economist at Natixis, echoed that view."
In the context of job market sluggish revival and continuous deleveraging of households, real estate remains the area of risk for the current economic recovery," Mufteeva said.
"Indeed, still-numerous foreclosures should keep home prices subdued in the medium term despite some improvement on the real estate market."
By AFP
