• NYSE goes public and acquires Arca and Euronext
• Nasdaq folds its interest in the LSE and acquires OMX as well as the Philadelphia and Boston Exchanges
• The NYSE moves toward electronic trading via its Hybrid Market Model
• The NYSE punts its Specialist model in favor of a Designated Market Maker function
• The SEC mandates faster electronic markets via REG NMS.
• Rule 500 eliminated
  • Companies now free to leave NYSE for NASDAQ
• Symbol Portability
  • Companies can take their symbol with them

Your trading is no longer centralized at the market that collects your listing fee. In fact, no market platform captures even so much as a third of the trading in its own listed companies.