Mitchells and Butlers (M&B), the restaurant and pub company behind the Harvester and O'Neill's chains, has rejected a takeover offer from its largest shareholder, the billionaire Joe Lewis. Evolution Securities believes that Lewis's 230p-a-share offer for M&B is priced at a "measly" premium and recommends shareholders to "sit tight", sending the share price soaring. Asset manager Ashmore Group saw its share price take a hit despite announcing record profits for the year to the end of June. Analysts following the company, which is set to make the leap to the FTSE 100, have voiced concerns over its performance fees. Peel Hunt said the results were "lower than hoped, but reflect the changing conditions in August." The broker added: "Ashmore is trading towards the top of the sector but we consider this is more than justified, given the rate of growth and continuing long-term potential from the asset class. "In the short term, the outlook looks less exciting, given pressure on forecasts and recent outperformances as the shares have held up well, partly on the recent entry to the FTSE." FTSE 250 - RisersMitchells & Butlers (MAB) 241.00p +9.50%Enterprise Inns (ETI) 35.05p +7.71%Charter International (CHTR) 859.00p +6.84%National Express Group (NEX) 235.00p +5.71%Gem Diamonds Ltd. (DI) (GEMD) 218.80p +4.19%Rathbone Brothers (RAT) 1,076.00p +3.56%Melrose (MRO) 289.30p +3.32%Perform Group (PER) 204.60p +2.81%BH Global Ltd. USD Shares (BHGU) 11.81 +2.16%BH Macro Ltd. EUR Shares (BHME) € 19.70 +2.02%FTSE 250 - FallersPremier Foods (PFD) 11.30p -7.30%Ashmore Group (ASHM) 381.40p -7.04%Morgan Crucible Co (MGCR) 246.00p -6.96%Talvivaara Mining Company (TALV) 285.20p -6.74%Big Yellow Group (BYG) 250.70p -6.63%International Personal Finance (IPF) 219.50p -6.56%Kofax (KFX) 290.30p -6.14%St James's Place (STJ) 317.10p -5.91%Salamander Energy (SMDR) 200.40p -5.65%New World Resources A Shares (NWR) 543.50p -5.64%NR