Home prices slipped in November and were softer than expected in the latest sign that a rebound in the U.S. housing market is still tenuous, according to Standard & Poor's/Case-Shiller indexes on Tuesday.

The S&P composite index of home prices in 20 metropolitan areas slipped 0.2 percent in November after a revised 0.1 percent October dip, for a 5.3 percent annual drop.

A Reuters survey had forecast a 0.1 percent November rise. Prices were originally reported as unchanged in October.

Up until a while ago it looked like home prices might have bottomed, said Suvrat Prakash, U.S. interest rate strategist at BNP Paribas. There might be a double dip in home prices, which could feed through to the rest of the economy, he said, adding that housing still faces many hurdles.

Several major government supports for housing are soon ending, including an extended and expanded home buyer tax credit for which buyers must sign contracts by April 30.

The end of such incentives just as mortgage rates rise and foreclosed properties start hitting the market could pressure prices anew, economists agree.

On a seasonally adjusted basis, the 20-city index rose 0.2 percent in November, S&P said, after a 0.3 percent rise the prior month.

The 10-city index declined 0.2 percent in November after being unchanged in October, for a 4.5 percent annual drop.

The home price picture remains mixed despite steady annual improvement, said David M. Blitzer, Chairman of the Index Committee at Standard & Poor's.

The pace of annual decline in home prices has improved for 10 straight months.

Only five of the markets saw price increases in November versus October, he said. What is more interesting is that four of the markets -- Charlotte, Las Vegas, Seattle and Tampa -- posted new low index levels as measured by the past four years.

Other markets continue to improve month over month, with Los Angeles, Phoenix, San Diego and San Francisco posting price increases for at least six consecutive months.

To add more mixed signals, we are in a seasonally weak period for home prices, so the seasonally-adjusted data are generally more positive, with 14 of the markets and both composites showing improved prices in November, Blitzer noted. On balance, while these data do show that home prices are far more stable than they were a year ago, there is no clear sign of a sustained, broad-based recovery.

A three-year housing market crash has swept prices back to levels seen in late 2003, according to S&P, boosting affordability.

From their peak in the second quarter of 2006 through November, the 10-city index has toppled 30 percent and the 20-city index has tumbled 29.2 percent

(Additional reporting by Burton Frierson)

(Editing by Theodore d'Afflisio)