Tullow Oil's topped the risers after Citigroup raised its rating on the stock from 'neutral' to 'buy', saying that the oil group's portfolio quality was "undervalued" by the market.Poundland was making gains after a trading update showed the discount retailer had topped a billion pounds of annual sales for the first time with revenue in final quarter excluding the Spanish business up 6.5%.Mining stocks were rebounding from heavy losses on Monday, when a number of investment banks shaved their price targets for iron ore over the coming years. Hunting, Lonmin, Kaz Minerals and Vedanta Resources were all trading higher.UK hospital operator Spire Healthcare dropped sharply after private equity group Cinven sold down its stake to 38.3% with a £136m share sale. Meanwhile, reports that Ithmar Capital was planning to sell a stake worth £216m in Dubai-based Al Noor sent shares into the red.Hiscox continued lower on news that chief financial officer Stuart Bridges would be leaving after 16 years in the role, to join interdealer broker ICAP. RisersTullow Oil (TLW) 367.50p +8.25%Soco International (SIA) 194.40p +7.28%Vedanta Resources (VED) 553.00p +6.86%Lonmin (LMI) 132.70p +5.65%Hunting (HTG) 586.50p +5.49%Premier Oil (PMO) 163.00p +4.96%Supergroup (SGP) 1,004.00p +4.37%Enterprise Inns (ETI) 115.30p +4.34%Bank of Georgia Holdings (BGEO) 2,049.00p +4.17%Kaz Minerals (KAZ) 227.70p +3.64%FallersSpire Healthcare Group (SPI) 331.30p -9.75%AL Noor Hospitals Group (ANH) 918.00p -7.51%Allied Minds (ALM) 705.00p -2.76%International Personal Finance (IPF) 475.40p -2.26%Hiscox Ltd (CDI) (HSX) 862.50p -2.16%Henderson Group (HGG) 295.60p -1.99%Carillion (CLLN) 322.00p -1.92%Polar Capital Technology Trust (PCT) 590.00p -1.91%Euromoney Institutional Investor (ERM) 1,140.00p -1.89%Home Retail Group (HOME) 171.10p -1.89%