The $10.3bn agreed merger between NYSE Euronext and Deutsche Börse received a boost with an agreement to take full ownership of Eurex, the German exchange operator's derivatives business, and the promise of a special dividend.

Deutsche Börse, which agreed to merge with NYSE Euronext on February 9, announced Tuesday that the Swiss stock exchange has agreed to sell its 50% share in derivatives exchange Eurex to Deutsche Börse, giving the German exchange full control of the highly prized electronic derivatives subsidiary.