The most awkward flash-crash possible

When your stock exchange wipes 99.75 per cent off its own value in less than a second, it might be t

Felix Salmon shows us his chart of the day, from Zerohedge (click for big):

He explains:

What you’re seeing here is the price of shares in BATS, at 11:14 [Friday] morning [ET]. The white spots are trades: there are 176 of them altogether. They start just below the IPO price of $16, and then just fall lower and lower and lower until the stock is trading for mere pennies. But the key number you want to look at here is not on the y-axis. Instead, it’s the chart report at the very top:

Elapsed Time: 900 Milliseconds

BATS, which stands for Better Alternative Trading System (a name which will surely come to haunt them), is a stock exchange based in Kansas. While most American stocks are listed in one of the two big exchanges, NYSE or Nasdaq, there are multiple venues where stocks can be traded – around 50. These exchanges communicate with each other to work out a "national best bid/offer" (NBBO), which is kept consistent throughout the venues. At least, that's the plan.

What appears to have happened is that a "software bug" (BATS aren't particularly forthcoming with the details) severed, or otherwise corrupted, the link between BATS and the NBBO system for all stocks beginning with A or B. This combined with the high-frequency trading that operates heavily in BATS (indeed, which it was largely set-up to enable) to allow stocks to plummet in less than a second.

For the most part, no-one was hurt. The error was confined to the one exchange, which rolled back the transactions. We would have all learned a valuable lesson about the dangers of computer-aided trading, the proponents of a financial transactions tax would have another weapon in their armoury (high-frequency trading isn't financially viable with a financial transactions tax in place), and everything would go back to normal. We would have, were it not for an excruciating coincedence:

The share that is charted above is that of BATS itself - that is, the company running the stock exchange which suffered the glitch. Not only that, it is the value of BATS on the day it held its initial public offering. Awkward.

BATS the company was supposed to be the first one to be listed (as opposed to merely exchanged) on BATS the exchange. For a smallish company based in a suburb of Kansas City, that is quite a big power grab. Needless to say, it didn't go to plan. The IPO is now cancelled, and the company has "no plans" to try it again soon. Which is unsurprising.

London 2004, back when trades were done by people, not Skynet. Credit: Getty

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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To stop Jeremy Corbyn, I am giving my second preference to Andy Burnham

The big question is whether Andy Burnham or Yvette Cooper will face Jeremy in the final round of this election.

Voting is now underway in the Labour leadership election. There can be no doubt that Jeremy Corbyn is the frontrunner, but the race isn't over yet.

I know from conversations across the country that many voters still haven't made up their mind.

Some are drawn to Jeremy's promises of a new Jerusalem and endless spending, but worried that these endless promises, with no credibility, will only serve to lose us the next general election.

Others are certain that a Jeremy victory is really a win for Cameron and Osborne, but don't know who is the best alternative to vote for.

I am supporting Liz Kendall and will give her my first preference. But polling data is brutally clear: the big question is whether Andy Burnham or Yvette Cooper will face Jeremy in the final round of this election.

Andy can win. He can draw together support from across the party, motivated by his history of loyalty to the Labour movement, his passionate appeal for unity in fighting the Tories, and the findings of every poll of the general public in this campaign that he is best placed candidate to win the next general election.

Yvette, in contrast, would lose to Jeremy Corbyn and lose heavily. Evidence from data collected by all the campaigns – except (apparently) Yvette's own – shows this. All publicly available polling shows the same. If Andy drops out of the race, a large part of the broad coalition he attracts will vote for Jeremy. If Yvette is knocked out, her support firmly swings behind Andy.

We will all have our views about the different candidates, but the real choice for our country is between a Labour government and the ongoing rightwing agenda of the Tories.

I am in politics to make a real difference to the lives of my constituents. We are all in the Labour movement to get behind the beliefs that unite all in our party.

In the crucial choice we are making right now, I have no doubt that a vote for Jeremy would be the wrong choice – throwing away the next election, and with it hope for the next decade.

A vote for Yvette gets the same result – her defeat by Jeremy, and Jeremy's defeat to Cameron and Osborne.

In the crucial choice between Yvette and Andy, Andy will get my second preference so we can have the best hope of keeping the fight for our party alive, and the best hope for the future of our country too.

Tom Blenkinsop is the Labour MP for Middlesbrough South and East Cleveland