The small-cap slump continued Thursday as the sector traded beneath the rest of the sliding market amid dropping names like WCI Communities ( WCI). WCI shares took a nosedive after the Florida-based homebuilder, which has explored selling itself and rejected a $22-a-share bid from financier Carl Icahn, announced it hasn't yet found another suitor. WCI said initial interest from several companies has waned in the wake of the beleaguered homebuilding and debt markets. Shares tumbled $2.42, or 21.4%, to $8.90. That helped to pressure the plunging Russell 2000 Index, which was down 23.01 points, or 2.8%, to 789.49. The S&P SmallCap 600, meanwhile, lost 2.6% to 415.94. ADA-ES ( ADES), of Littleton, Colo., slid 25.8% to $12.89 after halting its nascent relationship with Calgon Carbon ( CCC), with which it had struck a memorandum of understanding in March for jointly developing emissions-control products. ADA-ES said they "were unable to come to an agreement that reflected the business approaches of the two companies." Calgon Carbon shares were down 2% to $11.65. Meanwhile, application-software firm RightNow Technologies ( RNOW), of Bozeman, Mont., predicted a bigger non-GAAP loss of 45 cents to 50 cents and shaved its full-year revenue guidance down to $108 million to $110 million. Income should miss Thomson Financial's consensus by at least 9 cents a share; prior guidance had called for a loss of 31 cents to 39 cents a share on sales of $116 million to $120 million. Shares were off 15.1% to $13.62.