Halfords was heading up the FTSE 250 leaderboard after Oriel Securities changed its rating on the firm to "buy". The broker made the move despite revealing that the firm's trading update is likely to "breed lower consensus forecasts". In Oriel's view, however, the Halfords dividend is secure, which would preserve the juicy 7.4% dividend yield on the stock. New World Resources took a hit after JPMorgan Chase & Co.cut its price estimate by 44% and cut the projection for its London-traded shares from 940p to 530p. The broker maintained its "neutral" recommendation on the stock. Exillon was the biggest faller but it appeared to be a mystery mover with no reason coming to light for its tumble. FTSE 250 - RisersHalfords Group (HFD) 316.00p +7.30%Cranswick (CWK) 610.00p +3.65%Interserve (IRV) 299.80p +3.20%COLT Group SA (COLT) 99.95p +2.30%F&C Asset Management (FCAM) 63.20p +2.02%Paragon Group Of Companies (PAG) 144.60p +1.83%Daejan Holdings (DJAN) 2,356.00p +1.60%JD Sports Fashion (JD.) 845.00p +1.50%Sports Direct International (SPD) 221.80p +1.19%Debenhams (DEB) 55.50p +1.09%FTSE 250 - FallersExillon Energy (EXI) 221.20p -14.59%New World Resources A Shares (NWR) 440.00p -9.74%Lamprell (LAM) 239.70p -8.93%JPMorgan Russian Securities (JRS) 433.00p -8.46%Salamander Energy (SMDR) 177.60p -8.03%Thomas Cook Group (TCG) 36.07p -7.06%Centamin Egypt Ltd. (CEY) 98.35p -7.04%Brewin Dolphin Holdings (BRW) 120.00p -6.47%Fenner (FENR) 303.80p -5.92%Kenmare Resources (KMR) 37.82p -5.90%NR