The upside was being driven by Perform Group, which was rising strongly after a 58 per cent sell-off on Thursday. The digital sports media firm yesterday warned that full-year revenues would be under previous expectations, pushing earnings "significantly" below forecasts.UK residential property company Bellway was also higher after it said it has continued to experience strong demand for new homes, supported by low interest rates and government schemes. In a trading update for the period from August 1st to November 30th, the group said the average number of active outlets has increased by 5% to 224.Kazakhmys shares were lower after JPMorgan Chase & Co. reduced their target price on the stock from 200p to 180p. Africa-focused diamond miner Petra Diamonds fell despite saying it was upbeat about market conditions as it recorded 'solid prices' in its December tender of stones.FTSE 250 - RisersPerform Group (PER) 215.20p +19.56%Fidessa Group (FDSA) 2,277.00p +3.12%Ashtead Group (AHT) 731.00p +2.81%Dunelm Group (DNLM) 939.00p +2.12%Home Retail Group (HOME) 189.50p +2.10%Ferrexpo (FXPO) 175.70p +1.91%Redrow (RDW) 280.00p +1.89%Cobham (COB) 264.80p +1.85%Berendsen (BRSN) 918.00p +1.83%Greene King (GNK) 850.00p +1.80%FTSE 250 - FallersKazakhmys (KAZ) 191.40p -7.04%Partnership Assurance Group (PA.) 276.00p -6.69%Pace (PIC) 289.30p -5.43%AL Noor Hospitals Group (ANH) 920.50p -4.71%Xaar (XAR) 1,114.00p -4.13%Thomas Cook Group (TCG) 162.80p -2.92%Ophir Energy (OPHR) 303.00p -2.63%Centamin (DI) (CEY) 42.03p -2.39%Cairn Energy (CNE) 256.60p -2.10%Aveva Group (AVV) 2,078.00p -1.70%NR