This article brings up something that HF traders have been bemoaning for a long time: the fragmented US market structure. In US equities, you need to monitor almost a dozen exchanges to be competitive. The popular book &quot;Flash Boys&quot; gave the impression that HF traders loved this market structure and used it to extract more money out of the market. In the majority of cases, this is wrong.<p>In fact, the fragmented market results in huge costs (4 datacenters worth of infrastructure, low latency connectivity, etc) In reality, most market makers would vastly prefer to simplify this away. This is one of the reasons many traders have moved to alternative markets that have fewer trading venues (for example, many futures  and options trade primarily on a single venue)