Berkeley Group, Fidessa Group and Taylor Wimpey all dropped into the red after going ex-dividend on Wednesday. Balfour Beatty was in negative territory after rejecting another merger offer from rival Carillion, saying such a move would not be in shareholders' best interest. Tuesday's offer was the third one that Carillion has put on the table, but marked only a "small value change" compared to the preceeding two, in Balfour's view. A strong performance by its injectables business helped drive first half revenue growth of 16% at pharmaceuticals manufacturer Hikma, but investors appeared not to want to hang onto the stock. The figures were in line with those predicted by Panmure analysts, so it may be that shareholders are engaging in a round of profit-taking, given that the share price has risen close to 48% in the year-to-date.On the upside, FirstGroup was higher on expectations it could succeed in its bid for the Northern and TransPennine Express rail franchises. Its main competitor is Stagecoach. Keller was lifted by Numis, which upgraded the specialist ground engineering from 'add' to 'buy' with a target price of 1,070p.FTSE 250 - RisersFirstGroup (FGP) 126.00p +5.53%Diploma (DPLM) 671.50p +2.36%Keller Group (KLR) 883.00p +1.73%AL Noor Hospitals Group (ANH) 1,091.00p +1.21%Rightmove (RMV) 2,485.00p +1.14%Go-Ahead Group (GOG) 2,230.00p +1.09%Genus (GNS) 1,142.00p +1.06%Croda International (CRDA) 2,222.00p +1.00%Foxtons Group (FOXT) 287.00p +0.95%Micro Focus International (MCRO) 895.50p +0.90%FTSE 250 - FallersBerkeley Group Holdings (The) (BKG) 2,389.00p -7.51%Balfour Beatty (BBY) 238.00p -7.03%Hikma Pharmaceuticals (HIK) 1,710.00p -5.21%Perform Group (PER) 205.10p -4.20%Soco International (SIA) 428.80p -3.79%COLT Group SA (COLT) 141.20p -3.62%Domino's Pizza Group (DOM) 577.50p -3.51%Fidessa Group (FDSA) 2,172.00p -3.47%Taylor Wimpey (TW.) 114.70p -3.37%Computacenter (CCC) 604.50p -3.36%NR