Updated from 10:12 a.m. ESTHomebuilder stocks tumbled Tuesday after KB Home ( KBH) reported a $773 million quarterly loss and new data showed pending home sales fell more than expected in November. KB Home's fourth-quarter loss resulted from ongoing weak demand and plummeting margins, as land impairment charges and tax expenses came in higher than analysts projected. KB Home shares were down 8.6% to $16.89 in midday trading, hitting a 52-week low Other builders tumbled on the reports as well, with Meritage Homes ( MTH) dropping 11.9% to $10.11 -- also a 52-week low -- and WCI Communities ( WCI) falling 8.8% to $3.34. KB Home's quarterly loss amounted to $9.99 a share, compared with a loss of $49.6 million, or 64 cents a share, a year earlier. Analysts expected a loss of $1.08 a share. The Los Angeles-based builder said revenue fell 31% to $2 billion, reflecting the ongoing difficulties of getting buyers to close on their new home purchases. KB Home also said 2008 will be "another tough year" for the homebuilding industry. Also on Tuesday, the National Association of Realtors said its pending home sales index fell 2.6% in November from October -- worse than the 0.5% decline that economists expected, according to Reuters estimates. The index measures contracts of existing home sales.