Business process outsourcing specialist Xchanging falls sharply after it warned that revenue growth for the full year will be slightly lower than previously anticipated.Shares in Tullett Prebon are higher. The raid on staff by rival BGC in the second half of last year cost the inter-dealer broker 7% in revenue during the six months to June, but it still expects a "good" outcome for the year.First half revenue of £475.8m was down 8% from £517.9m a year ago as the broker defections in North America caused a 30% slump in fixed income revenue to £132.7m.Taylor Wimpey is higher ahead of the housebuilder's results tomorrow's half year results. Peer Persimmon is also going strong.FTSE 250 - RisersRedrow (RDW) 115.10p +7.47%Tullett Prebon (TLPR) 362.80p +6.58%Persimmon (PSN) 376.10p +6.51%Taylor Wimpey (TW.) 28.13p +6.15%Debenhams (DEB) 65.25p +6.10%Victrex (VCT) 1,294.00p +6.07%Ferrexpo (FXPO) 293.50p +6.03%John Wood Group (WG.) 379.20p +6.01%Salamander Energy (SMDR) 253.80p +5.57%Hochschild Mining (HOC) 304.50p +5.22%FTSE 250 - FallersXchanging (XCH) 174.00p -13.00%Premier Foods (PFD) 18.49p -2.63%Connaught (CNT) 34.89p -2.05%TalkTalk Telecom Group (TALK) 120.00p -2.04%Yell Group (YELL) 23.57p -1.83%EnQuest (ENQ) 115.00p -1.71%Eaga (EAGA) 104.20p -1.70%Moneysupermarket.com (MONY) 68.85p -1.64%Rathbone Brothers (RAT) 818.50p -1.39%Dimension Data Holdings (DDT) 121.40p -1.30%