Thomson ReutersThe New York Stock Exchange is fighting back in a fierce debate over the cost of accessing the market. The war of words is the latest in a long-running battle over the cost of data, connectivity and colocation, and was triggered by the Big Board's request to change the fees it charges for certain connectivity services. When the Securities and Exchange Commission sought additional comment on the request, those who believe these services have gotten too expensive jumped at the chance to take shots at the exchange. Now, NYSE is returning fire, taking aim at some of its biggest customers. In a letter to the regulator dated January 17, NYSE said that the questions raised in the Commission's Order Instituting Proceedings are moot, as NYSE is no longer pushing ahead with the changes the Order was focused on.