" As far as narrowing spreads, that’s absolutely true, but in absolute terms what does it translate into? For the individual investor it might save them a quarter a month. " In a properly designed, information age stock market there should not be a spread. All stocks should trade via a programmed, black box auction that runs on an interval. The HFT practice of creating phony orders that are immediately canceled, just…
Precisely why it doesn't work that way.