Countless studies point to a lowering in bid-ask spreads (the effective "fee" impatient traders pay to trade) when electronic market-makers entered the market,

Countless studies point to a lowering in bid-ask spreads (the effective "fee" impatient traders pay to trade) when electronic market-makers entered the market, and an increase in this spread when they leave or are forced out: http://marginalrevolution.com/marginalrevolution/2014/04/a-study-of-limiting-hft.html http://marginalrevolution.com/marginalrevolution/2014/04/a-s... For me to win trades as a market-maker, I have to put up prices that are tighter (buying higher and selling lower) than my competitors. Through this competitive process, the rents earned by market-makers decrease and the end consumer of their liquidity reaps most of the benefit. Since markets have moved away from a monopoly specialist model and become more electronic, spreads (and thus compensation earned by market-makers) have decreased dramatically. Nobody is backing it up because a.) firms involved tend to be secretive so as not to give away any competitive information, b.) there are a lot of slow or inefficient brokers speaking out against it "talking their book", and c.) to the end-user, HFT is like plumbing. I don't thank the city workers every time I hop in the shower, or write a glowing blog post about Visa when I swipe my card to buy goods and services all over the globe. The infrastructure exists and it provides a benefit, but it's faceless and not something most people think about. Most people don't even consider who is on the other side of their trades or where the prices even come from. They just want to click a button and get in or out of a position, and thanks to competing HFTs they can do it instantly, cheaper than ever before.