Why Wall Street is scoffing at 'flash crash' bust

'Inconsistencies glaring': Lopresti on 'Flash Crash' arrest

In arresting Navinder Sarao this week and charging him with manipulating markets, regulators indicated they'd gotten to the bottom of 2010's "flash crash." Many on Wall Street, though, believe the work is only starting.

That's probably a gentle way of stating the Street's reaction to Sarao's arrest Tuesday. Many pros openly scoffed at the notion that Sarao was the sole culprit of the spectacular plunge on May 6, 2010. On that day, the Dow industrials rapidly lost about 600 points, taking the average down nearly 1,000 points on the session, only to rebound within a matter of minutes.

According to separate indictments, Sarao masterminded a scheme in which he was able to send orders to the market that he had no intention of executing, a practice called "spoofing" that caused a market plunge on which Sarao capitalized. The practice happened within minutes of the crash and was a direct cause of it, according to regulators. Authorities allege he acted mostly alone rather than as part of a large, sophisticated operation.

However, many experts believe the explanation is at least an oversimplification and at most an intent to deflect attention away from more fundamental weaknesses in the financial markets.

"The real issue here is that markets have dramatically changed over the past two decades but regulators have not kept up," Joe Saluzzi and Sal Arnuk, who run Themis Trading and have been ardent supporters of changes to market structure, said in a blog post Thursday. "While technology has increased efficiency and brought down trading costs, it has also changed the way traders access the markets."