&gt; Fragmented exchanges are better for everyone except for high frequency traders. Then they actually have to do low latency arbitration to make money instead of full on front running like they do now.<p>This is a very strong statement with little support. I agree that some competition among exchange operators is important, but how do you justify exchanges like CHX, with approximately 1% market share?<p>I am not sure how to respond to your comment regarding front running without more detail. Many sources have already debunked the Michael-Lewis-style argument regarding front running. Where do you see front running? (Using the proper definition of trading ahead of a customer order based on knowledge of that order)