Russia-focused steelmaker Evraz surged after pledging to buy-back shares despite reporting a net loss of $1.28bn last year.FirstGroup rose strongly after saying trading for the year to the end of March had remained in line with expectations, with progress continuing on its medium-term transformation plans.Support services group Serco continued higher after agreeing the £2.5m sale of its Australian Great Southern Rail Business on Tuesday.Animal genetics group Genus topped the fallers as it completed the acquisition of a 51% stake in biotechnology firm Vitro Brasil for an undisclosed amount.RPC reversed from gains made on Tuesday, when the plastic packager announced it expected annual revenue and adjusted operating profit to be in line with expectations and "significantly" ahead of last year.Thomas Cook was among the fallers, despite announcing on Tuesday that it had taken confidence from improved trading in continental and northern Europe in recent weeks. RisersFirstGroup (FGP) 96.45p +6.05%Evraz (EVR) 198.60p +5.81%Marston's (MARS) 159.40p +4.66%Serco Group (SRP) 143.60p +4.13%Cable & Wireless Communications (CWC) 63.35p +3.94%Card Factory (CARD) 306.20p +3.69%Telecom Plus (TEP) 900.00p +3.45%Go-Ahead Group (GOG) 2,405.00p +3.22%Hiscox Ltd (CDI) (HSX) 878.00p +3.17%TalkTalk Telecom Group (TALK) 353.30p +2.67%FallersOcado Group (OCDO) 340.30p -3.82%Genus (GNS) 1,320.00p -3.58%NMC Health (NMC) 641.50p -3.46%Drax Group (DRX) 352.10p -3.24%Thomas Cook Group (TCG) 141.90p -2.61%Worldwide Healthcare Trust (WWH) 1,880.00p -2.59%Home Retail Group (HOME) 161.20p -2.30%RPC Group (RPC) 567.50p -2.16%Supergroup (SGP) 934.50p -2.10%Bodycote (BOY) 704.00p -2.09%