Oil stocks were leading the FTSE 250 downwards on Tuesday as US crude prices dropped to their lowest in three years. The slump came as the world's largest exporter, Saudi Arabia, lowered prices for crude exports to US customers in an attempt to support its market share.Producers Ophir Energy, Afren, Premier Oil and Enquest fell sharply, while oil services peers Amec, Hunting and Wood Group also slumped.Leading the risers was fund manager Man Group after Credit Suisse said it was "turning more positive" on the European asset-management sector and rated the stock 'outperform'. The bank said that Man should deliver "best-in-class" earnings and dividend growth over the next three years.Unite Group was also making gains after the student accommodation manager reported a "very strong lettings performance" in the third quarter with demand still high for its rooms.Insurance broker Jardine Lloyd Thompson saw shares sink after reporting a continued decline in the insurance and reinsurance rating market in the third quarter. FTSE 250 - RisersMan Group (EMG) 129.70p +5.11%NMC Health (NMC) 508.00p +4.25%RPC Group (RPC) 552.00p +3.66%Crest Nicholson Holdings (CRST) 342.70p +2.85%Synthomer (SYNT) 206.20p +2.84%Unite Group (UTG) 438.30p +2.81%Diploma (DPLM) 727.50p +2.75%Greencore Group (GNC) 263.20p +2.25%Thomas Cook Group (TCG) 127.70p +2.08%Hiscox Ltd (CDI) (HSX) 689.50p +2.07%FTSE 250 - FallersOphir Energy (OPHR) 176.30p -7.16%Afren (AFR) 70.10p -6.72%Amec (AMEC) 992.50p -6.01%Premier Oil (PMO) 242.90p -5.34%Jardine Lloyd Thompson Group (JLT) 890.00p -5.32%Regus (RGU) 186.30p -4.46%Cairn Energy (CNE) 142.20p -4.11%Hunting (HTG) 703.50p -4.02%Wood Group (John) (WG.) 640.00p -3.76%EnQuest (ENQ) 67.25p -3.72%
