African Barrick Gold is a top performer after having further successes with its drilling programme on the Nyanzaga project in Tanzania.Euromoney Institutional Investor, the business publisher and exhibitions organiser, is among the fallers after its pre-close trading update underwhelmed investors. While the firm is trading in line with expectations in the half-year to 31 March, it warned that delegate sales for the training business have "struggled" to achieve year-on-year growth.Gaming firms PartyGaming and Betfair are firmer after sector peer 888 rose 10% on the back of positive news from the Nevada Gaming Commission. Budget airline easyJet is edging lower after its target price was slashed by 32% by Credit Suisse, after accounting for higher fuel prices and limited growth next year. The broker kept its 'neutral' stance.Also hit by broker comments is construction products supplier SIG, after RBS said a lack of operational gearing is a key concern facing the sector. Nevertheless, the broker kept its 'buy' rating.BCFTSE 250 - RisersPartyGaming (PRTY) 195.50p +4.88%Centamin Egypt Ltd. (CEY) 137.80p +4.08%SVG Capital (SVI) 248.60p +4.02%Drax Group (DRX) 386.00p +3.79%African Barrick Gold (ABG) 547.50p +3.50%Betfair Group (BET) 968.50p +2.98%Salamander Energy (SMDR) 295.90p +2.96%Savills (SVS) 367.60p +2.91%Travis Perkins (TPK) 1,039.00p +2.87%Dixons Retail (DXNS) 17.31p +2.67%FTSE 250 - FallersRedrow (RDW) 130.00p -4.55%Cable & Wireless Communications (CWC) 47.13p -2.88%Taylor Wimpey (TW.) 42.10p -2.79%Micro Focus International Plc (MCRO) 307.20p -2.78%Paragon Group Of Companies (PAG) 173.80p -2.52%Ultra Electronics Holdings (ULE) 1,672.00p -2.45%SDL (SDL) 658.00p -2.45%Daily Mail and General Trust (DMGT) 502.50p -2.43%Homeserve (HSV) 439.50p -2.38%Bovis Homes Group (BVS) 453.90p -2.32%