Investors are taking a punt on Sportingbet after the online bookmaker confirmed it is in merger talks, rumoured to be with Swedish rival Unibet in a deal that could be worth up to £600m.Pork specialist Cranswick is posting meaty gains after it served up a 12% increase in half year pre-tax profit, hiked its dividend and said it was confident for the second half.Premier Oil gushes higher on talk that state-controlled KNOC, the Koreans who recently paid £1.9bn for Dana Petroleum, also have the North Sea oil group in their sights.The chips are down for Imagination Technologies again. It is today's heaviest faller adding to losses at the end of last week that came amid speculation it lost out on a contract with mobile phone group Samsung to rival ARM Holdings.FTSE 250 - RisersSportingbet (SBT) 61.95p +5.99%Kenmare Resources (KMR) 25.95p +5.92%Cranswick (CWK) 828.50p +5.41%PartyGaming (PRTY) 223.50p +4.88%JD Sports Fashion (JD.) 800.00p +3.83%Premier Oil (PMO) 1,860.00p +3.45%Salamander Energy (SMDR) 238.80p +3.42%Spectris (SXS) 1,220.00p +3.39%Ferrexpo (FXPO) 391.80p +3.32%Yell Group (YELL) 11.14p +3.24%FTSE 250 - FallersImagination Technologies Group (IMG) 342.80p -5.38%Taylor Wimpey (TW.) 25.00p -3.74%Berkeley Group Holdings (BKG) 808.50p -3.12%Barratt Developments (BDEV) 76.95p -2.96%Savills (SVS) 359.70p -2.63%Sports Direct International (SPD) 130.60p -2.39%BTG (BGC) 252.50p -2.13%Yule Catto & Co (YULC) 251.90p -2.06%Stagecoach Group (SGC) 205.70p -1.67%Aquarius Platinum Ltd. (AQP) 377.00p -1.67%