"The speed in which the rises and falls occur might last no longer than half a second, unapparent to any human who is tracking prices. Johnson says if you blink you miss it. Flash events may happen in milliseconds and have nothing to do with a company’s real value.
To examine such incidences and their frequency the authors of the study waded through price logs from over 60 markets collected by Nanex, a Chicago company that sells streaming market data. The data revealed that the ultrafast fracture events were not infrequent but common, totaling 18,520 in the 2006 to 2010 time span. The authors looked for extreme changes in a stock price, which they defined as a change greater than 0.8 per cent, over timescales shorter than 1.5 seconds.
The speed in which ultrafast events happen is of concern as human oversight becomes impossible if trades are taking place faster than humans can react. Machine trading today carries computerized trading algorithms that make automated trades in milliseconds and make some experts uncomfortable, in the fear that out-of-control algorithms can cause a crash."
Should we just let traders do whatever they want, even if it destabilizes the entire system? Capitalism requires oversight. That's just a historical fact.