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By Scott Malone

BOSTON, June 27 (Reuters) - KB Home (KBH.N: Quote, Profile, Research), the No. 5 U.S. home builder, posted a wider-than-expected quarterly loss on Friday on tumbling revenue as the United States faced its worst housing slump in decades, sending its stock falling almost 6 percent.

KB, which has a large presence in the southwestern United States, reported a net loss of $255.9 million, or $3.30 per share, in its second quarter, compared with a loss of $148.7 million, or $1.93 per share, last year.

Factoring out a $98.9 million valuation allowance charge, the loss came to $2.03 per share in the quarter, compared with the average Wall Street loss estimate of 90 cents a share, according to Reuters Estimates.

Revenue plunged by more than one-half, to $639.1 million from $1.41 billion, hurt by a 41 percent decrease in the number of homes sold and a 17 percent decline in average price.

"Persistently poor demand for new homes during the second quarter amplified pricing pressures and diminished asset values in many of our served markets," said Jeffrey Mezger, the company's president and chief executive. "Potential new home buyers remain reluctant to purchase a home."

KB said net new home orders fell 42 percent in the quarter to 4,200.

The result comes a day after No. 2 U.S. home builder Lennar Corp (LEN.N: Quote, Profile, Research) reported a deeper-than-expected loss, saying that it saw no sign that market conditions would improve this year.