(CNBC) Stock futures were flat on Wednesday evening, as investors await the next market catalyst. Futures linked to the S&P 500 ticked higher by 0.01%, while Nasdaq 100 futures inched up by 0.01%. Futures tied to the Dow Jones Industrial Average dropped 12 points or 0.04%. In after-hours action, GameStop shares tumbled roughly 19%. The video game retailer fired its CEO Matthew Furlong and appointed Ryan Cohen as its executive chairman.