(ShareCast News) - The FTSE 250 was in the black for most of Wednesday, before a sharp fall late in the afternoon sent it into the red.The second-tier market was down 2.79 points (0.02%) to 16,685.12 under an hour before the market was due to close.Oil and gas producers and service providers were up as oil begin to rebound somewhat. Tullow Oil led the risers, up over 10%, as well as Ophir Energy and oil services companies Weir Group and Petrofac. It followed oil prices dipping below $30 a barrel on Tuesday night, but by 1511 GMT West Texas Intermediate crude was up 4.07% to $31.68 a barrel, while Brent crude was up 3.05% to $31.80.Miners Centamin and Acacia Mining were also up as confidence was restored somewhat in China, the world's largest commodities importer. Data showed China's trade surplus widened to 382.05bn yuan in December from 343.10bn yuan in November, beating analysts' forecasts of 338.80bn yuan.Exports rose unexpectedly by 2.3% in December following a 3.7% dip a month earlier. Economists had pencilled in a 4.1% drop. Imports declined 4% last month, compared to analysts' estimates for a 7.9% fall and November's 5.6% slide. "China's trade data for December support our view that, despite the turmoil in Chinese financial markets, there has not been a major deterioration in its economy in recent months," according to Capital Economics. "Meanwhile, another large trade surplus last month provides a cushion for the People's Bank in the face of soaring capital outflows."Investors also saw hope in Home Retail as Sainsbury's issued its third quarter trading update and providing more details about its plans to take over the FTSE 250 company.The supermarket's chief executive Mike Coupe said on a conference call that the company will "only pay what we can afford to pay" for Home Retail was rebuffed, adding that he will look for other opportunities if no deal is reached with the Argos and Homebase owner. Coupe said the non-food scale of the potential merged entity would match John Lewis or Amazon UK. One of the reasons Sainsbury's has been looking at Argos is for its much-admired hub-and-spoke logistics capabilities and multi-channel strength.Mitie led the market's fallers after Barclays downgraded the stock from 'equal weight' to 'underweight', citing below consensus forecasts and cost pressures increasing."FY15 results last May brought to an end a three-year period of significant one-off items and non-core losses relating to Mitie's exit from M&E contracting and Asset Management activities with management promising numbers would be 'clean in sixteen'," the investment bank said. However it noted while the results in November show it's on track for this, the overall underlying performance was disappointing.Shares in homewares retailer Dunelm Group also sank after it said the mild weather has seen the number of people entering its stores decrease, but home delivery sales are on the rise.The group's total sales for the latest quarter clocked in at £245.7m, with the majority of sales made in store, while home delivery sales increased 23.4% to £16.5m. However, underlying like-for-like performance was adjusted down to -0.8% for the quarter due to more days of its Winter Sale in the reporting period.FTSE 250 - RisersTullow Oil (TLW) 135.80p 10.32%Electrocomponents (ECM) 237.90p 6.40%Weir Group (WEIR) 896.50p 5.22%Ophir Energy (OPHR) 85.25p 4.73%Centamin (DI) (CEY) 65.00p 4.42%G4S (GFS) 224.90p 4.12%Home Retail Group (HOME) 147.70p 4.09%Acacia Mining (ACA) 178.40p 4.02%Just Eat (JE.) 474.40p 3.74%Petrofac Ltd. (PFC) 693.00p 3.66%FTSE 250 - FallersMitie Group (MTO) 282.20p -6.25%BBA Aviation (BBA) 172.10p -5.65%Aldermore Group (ALD) 205.80p -3.74%Dunelm Group (DNLM) 872.00p -3.65%Jimmy Choo (CHOO) 130.40p -3.41%Laird (LRD) 343.30p -2.89%Aveva Group (AVV) 1,442.00p -2.70%Mitchells & Butlers (MAB) 291.50p -2.57%Poundland Group (PLND) 163.40p -2.56%Go-Ahead Group (GOG) 2,514.00p -2.44%