The proposed $10.2bn merger between NYSE Euronext and Deutsche Börse may have overcome the challenge of a vigorous counterbid led by Nasdaq OMX, but a potentially bigger test looms: gaining the approval of the European Commission.

The two exchanges, which agreed in February to a merger that would create one of the world's largest cash and derivatives trading platforms, still await the all-important nod from Europe's competition commissioner Joaquín Almunia.