Exchange ratio

Why is it so difficult to push together two large stock exchanges? Despite 18 months of talks and flirting, the bosses of the big US and European bourses have yet to come up with a deal that passes muster. Look at Euronext, for instance. The European exhange hasn’t managed to extract a premium for its shareholders, despite having two suitors to choose from - NYSE Group of the US and Deutsche Boerse. The Germans actually had the gall to offer Euronext’s boss, Jean Francois Theodore, a sizeable d...