The commission rejected the merger on antitrust grounds, saying the combined businesses would dominate Europe's on-exchange derivatives trading with an estimated 93% market share. "This is a black day for Europe and its global competitiveness on financial markets", said former Deutsche Börse chief executive Reto Francioni. NYSE Euronext chairman Jan-Michiel Hessels said: "While we are disappointed and strongly disagree with the EU decision, which is based on a fundamentally different understanding of the derivatives market, it is now time to move on".