Shares in National Express raced ahead after it emerged fellow bus and train group Stagecoach is in exclusive discussions with the bidder for National Express to acquire some of its businesses if the offer goes through.Shares in business publisher Informa are lower ahead of the company's 2009 results tomorrow. But peer UBM, which delivers interim results on Monday, are among the top 10 percentage risers.FTSE 250 - RisersAquarius Platinum Ltd. (AQP) 251.00p +5.24%Talvivaara Mining Company (TALV) 373.25p +4.55%National Express Group (NEX) 360.25p +4.19%Yell Group (YELL) 32.25p +4.03%Aveva Group (AVV) 795.50p +3.72%Morgan Crucible (MGCR) 114.75p +3.61%United Business Media (UBM) 405.25p +3.18%Mondi (MNDI) 253.75p +2.73%Stobart Group (STOB) 103.75p +2.72%ITV (ITV) 38.75p +2.65%FTSE 250 - FallersBig Yellow Group (BYG) 331.75p -5.01%Bodycote (BOY) 124.50p -4.96%Mcbride (MCB) 150.25p -4.60%Brown (N.) Group (BWNG) 232.00p -4.03%Hunting (HTG) 423.00p -4.03%DSG International (DSGI) 24.00p -4.00%Enterprise Inns (ETI) 127.00p -3.97%Debenhams (DEB) 86.25p -3.90%Informa (INF) 250.25p -3.84%Persimmon (PSN) 422.25p -3.65%