ART CASHIN: The 'flash crash' happened 5 years ago today, and traders from London to NY are still buzzing about it

It's the fifth anniversary of the flash crash.

On May 6, 2010, the Dow fell by about 1,000 points within minutes, leading to chaos and confusion on the floor of the New York Stock Exchange.

In a morning email, Wall Street legend Art Cashin reflects on the crash, and on the ongoing legal case.

Here's Cashin:

As you've probably heard a million times already, today is the Anniversary of the Flash Crash in 2010. The approach of the anniversary and some recent doings in London have prompted some very animated chatter and lots of recollections of the events of that day.

As to the London doings, trading desk chatter seems to focus on two points. First, what about rumors that the trader in question may have shut down his system two minutes before the flash crash began? Secondarily, traders wonder why, if he was making the kind of money the media claims that he couldn't make bail.

On the crash itself, traders agree that the new range collars can be helpful but that little has been done on order routing incentives.

Many traders think that a key component of the Flash Crash was rebate policy. That induced some firms to have their computers route orders to the venue with the most lucrative (for the sender) rebate rather than the venue with the best market.

When things started to destabilize, market-makers in many markets pulled virtually all their bids, leaving only a "placeholder" bid of a penny, assuming, no one would hit such a low bid. Instead, the computers kept routing to the presumed rebate venues and hitting those placeholder bids.

Luckily, nothing traded for a penny on the floor of the NYSE. Maybe that's because humans are still involved.

Futures trader Navinder Sarao was arrested in London on April 21 for allegedly spoofing the market and contributing to the crash. He is fighting extradition to the US.

Here's the crazy chart that shows just how crazy things were in the market that day.