While Europe's stock exchanges play a drawn-out game of cat and mouse, in the US consolidation is happening, with the merger between the New York Stock Exchange and Archipelago, and Nasdaq acquiring the Inet trading platform. Combined with Regulation NMS, the new rules governing trading that allow investors to use the fastest exchange rather than just the best price, it amounts to a dramatic overhaul of equity markets. Players from all sides predict what the impact will be.

Chris Concannon, Executive vice-president, transaction services, Nasdaq