Shares of KB Home and Ryland Group Inc. slipped Friday amid industry-wide concern that the national real estate slump may last longer than anticipated.

KB Chief Executive Jeff Mezger, interviewed by Reuters on Thursday, said that he does not expect the U.S. home market to bottom out until the end of next year and predicted prices will not increase until well into 2009.

“By the end of ’08 it will start to stabilize,” Mezger said in the interview. “Then it will start to go back up in ’09. I think it will take a year.”

Mezger’s remarks followed comments by Fed Chairman Ben Bernanke earlier this week that the national housing market might get worse before it improves, adding that the protracted decline is hitting consumer spending and overall economic growth.

And two weeks ago the two local homebuilders were downgraded by Citigroup, which cited waning demand for new homes and mounting inventories as key reasons the two stocks will not perform.

The housing slump has taken a toll on homebuilders. A gauge of 16 homebuilders in the S & P; index has dropped nearly 30 percent so far this year. Shares in KB have lost 38 percent, while shares in Ryland have lost 42 percent.

Shares in Los Angels-based KB lost 4 percent, or $1.45, to $34.87 in afternoon trading Friday on the New York Stock Exchange. Shares in Ryland dipped 3.4 percent, or $1.24, to $34.98.