I found a nice piece on forbes tonight. It shows how rulemakers are Always running behind on the markets. The eu has passed a new law trying to controle the market. What it basically comes down to is this.
“The curbs are part of revamped EU markets legislation ranging from commodity derivatives speculation to investor protection. The high-frequency trading limits include standards meant to keep the price increment for securities from being too small, mandatory tests of trading algorithms and requirements that market makers provide liquidity for a set number of hours each day.”
The whole idea of high frequency trading is just that you can buy and sell so extremly fast on a very small spread. Something regular investors could never do. Check out the whole forbes article here