Wall Street did normalize after the Dow dropped a harrowing 600 points in just a few minutes last year, but some investors say not enough is being done to prevent another Flash Crash.

A year after the Dow plunged 600 points in minutes, professional investors fret about risks in a market where they are outmanned by machines.

Regulators have put in place rules to keep stocks from tumbling to zero, but skeptics question their adequacy.

It's been one year since the flash crash on Wall Street. The SEC's Mary Schapiro discusses the measures taken since then to try to prevent a repeat.

Experts have advised U.S. financial regulators to place tougher rules on high-speed computer trading to prevent a sequel to the May 6 "Flash Crash." But technology is driving stock markets to merge, raising questions about whether bigger exchanges will make things worse. New York bureau chief Heidi Moore reports.

Experts advise U.S. securities regulators impose tougher rules on high-frequency trading to prevent a sequel to the May 6, 2010, "flash crash."

Because milliseconds matter in the world of high-frequency trading, the new cables being laid between New Jersey and London will take cable speed from 65 milliseconds to below 60 milliseconds.

Federal regulators are still looking into the causes of the so-called flash crash that happened back in May. The Securities and Exchange Commission says it may have some new leads. Reporter Jeremy Hobson talks about what the SEC's latest findings are.