It’s been a while now since high-frequency-trading (HFT) made its debut in the financial market landscape. Initially, little was known about it and regulators and market participants alike were naturally concerned about its potential impact on markets. Nevertheless, over the past few years we have learned quite a bit more about HFT. So what’s the deal with HFT? This short blog post briefly describes the evolution of HFT, summarizes the current understanding of the impact of HFT on market quality and highlights some aspects of HFT activity that are still contentious. Regardless, I believe, the inescapable conclusion that so far emerges is that HFT has mostly had a positive impact on market functioning.