2010 data? Wow! That's funny.
Here's something a bit more recent.
Your (2017) link:
"Where does HFT go from here?
"As consolidation becomes the order of the day in the HFT industry, this could have a disruptive impact of the rest of the marketplace.
"For example, with the acquisition of KCG, Virtu will effectively control one fifth of the US equity market.
"So what does this mean for market making going forward?
"'Any time you have consolidation with one or two firms providing all of the liquidity, you’re more likely to see short-term volatility. You’ll also have consolidation of information, and there is a lot of value in information. With consolidation in multiple asset classes there could also be a disruption in correlations,' adds Rival’s D’Arco."
Which sounds like another version of monopolistic rent-seeking.