Nasdaq, the US stock market, more than doubled net profits to $17.1m (€14.1m) in the fourth quarter of last year after taking over Instinet, the electronic trading network, which helped it build market share in period of rapid consolidation in the US trading business.

Expenses in the fourth quarter were $105.4m and included the impact of workforce reduction and a review of the exchange's technology. They included a pre-tax charge of $2m relating to the exchange's efforts to reduce operating expenses and to integration of Instinet's trading platform, Inet.