Bob Greifeld, chief executive of Nasdaq OMX, said large exchange mergers are still possible despite regulators blocking the proposed merger between NYSE Euronext and Deutsche Börse and his own attempts to buy his US rival.

This morning the European Commission blocked the attempted deal between NYSE Euronext and Deutsche Börse on the grounds that it would create a monopoly in the European derivatives trading market. Last year the US Department of Justice also blocked a joint hostile bid by Nasdaq OMX and the IntercontinentalExchange for NYSE Euronext which attempted to disrupt the agreed deal.