NYSE Euronext is taking back control of its systems development from its main technology supplier, which this year parted ways with its chief executive and chairman, as the world's largest exchange faces up to the challenge of integrating its European and US trading platforms.

The transatlantic exchange, which formed in April, has paid Atos Origin €275m ($400m) for half of Atos Euronext Market Solutions, the joint venture between the IT consultancy and Euronext set up in 2005 to handle systems development for the exchange.