How Many Exchanges Does The World Need?

Among the many financial trading and IT conferences I have attended over the years - from TradeTech in Paris to Burgenstock in Montreux, Switzerland, and beyond - the question has always arisen as to how many stock and derivatives exchanges there would be in three, five or ten years time. Depending on who you canvassed the answer would always be different. Perhaps not that surprising I suppose. Some pundits suggested that in the end analysis there would be five or six global exchange groups.