It saddens me that people lump Market Making and HFT together. Over the past 100 years, the bid-ask spread has fairly steadily decreased due to technology and

It saddens me that people lump Market Making and HFT together. Over the past 100 years, the bid-ask spread has fairly steadily decreased due to technology and this fact in isolation is uniformly a good thing for retail investors. http://www.cxoadvisory.com/5737/big-ideas/trading-frictions-over-the-long-run/ http://www.cxoadvisory.com/5737/big-ideas/trading-frictions-... Other HFT methods are less clearly on net socially good.