The changing market of markets

I had mentioned during the lecture on markets that there have been dramatic changes in markets in recent years (e.g., mergers of markets, NYSE going public, Nasdaq becoming an exchange) and that it is likely that we would see changes during the semester. A significant change was announced today: NYSE Euronext (the parent of NYSE) is acquiring the American Stock Exchange: http://online.wsj.com/article/SB120060675290298637.html