Robert Greifeld, chief executive of Nasdaq OMX, joked at a conference presentation last month: “Do I really have to talk about the equities business?” Greifeld’s presentation showed only 12% of the exchange’s net profits of $455m last year came from equities, with global data products providing the largest share at 35%. This highlights the changing role of exchanges since they have transformed from member-owned utilities to public, profit-making companies.

Many exchanges are pushing further into the technology sales and infrastructure business to diversify their revenue base. But this is increasingly bringing them into competition with their broker clients. And now, Nasdaq OMX plans to blur this line even further by selling trading algorithms - pending regulatory approval by the Securities and Exchange Commission - a service traditionally provided by its broker clients.