The awkward mathematics of booms and bubbles

When short and long aren't opposites.

One of the most common responses in the many, many comments to my pieces on Bitcoin over the last couple of weeks has been to ask me why, if I'm so sure it's a bubble, I don't short it.

The simplest answer is that journalism isn't a career which leaves a huge amount of money left over after the bills are paid with which to gamble, and that I'm not entirely sure it's ethical anyway. There's also the fact that the two main Bitcoin meta-exchanges aren't particularly liquid, which leaves me doubtful that I'd get the best value for money on any shorting contract,

Then there's the problem that being pretty certain the bubble is going to pop doesn't leave me any surer about when it's going to pop – something which most methods of shorting require you to know.

Shorting usually involves borrowing the thing you want to short for a fixed amount of time, selling it straight away, and then buying it back just before your loan is up. Ideally, the commodity has dropped in value, and so you make a profit by you pocketing the difference.

In a normal commodity, going short and going long – buying the commodity to sell at a higher price – are roughly symmetrical. If a share in Apple goes up $1, the people who are long make a dollar a share; if it goes down, the people who are short do.

But that symmetry breaks down when you're dealing with a commodity on the sort of parabolic trend that Bitcoin is shooting along now.

If I spend £100 on Bitcoin, then the most I can lose is £100. Conversely, if the trend continues, I could have £1000 in a month. And the maximum possible payoff is basically uncapped. Suppose I'm catastrophically wrong, and Bitcoin becomes the world currency by the end of the year – anyone who'd bought in to it, even at today's inflated prices, would be a millionaire.

But what if I short it, by borrowing £100 of Bitcoin? Well, then the most I can earn is £100, if the price drops to zero. But the amount I could lose is potentially uncapped, for the exact same reasons that make buying in to it so appealing.

That lack of symmetry – which is an innate feature of, well, maths – serves only to goose the bubble higher and higher. And at the other side, when the down swing comes, it will be vicious; with no shorters ready to step in and buy the coins of people trying to cash out, the volatility will have nothing dampening it.

So that's why I'm keeping my money where it is. But don't think I'm not pretty damn confident when I say that if I had any extra, it still wouldn't be in Bitcoin.

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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Politicians: it's no longer OK to know nothing about technology

It’s bad enough to joke about not being "techy"; it's worse to write a piece of legislation from a position of ignorance. 

Earlier this week, facing down a 600-strong battalion of London’s tech sector at a mayoral hustings in Stratford, Zac Goldsmith opened his five minute pitch with his characteristic charm. “I’m not very techy!” he exclaimed. “I understand coding about as well as Swahili!”

Pointless jibe at a foreign language aside, this was an ill-chosen way to begin his address - especially considering that the rest of his speech showed he was reasonably well-briefed on the problems facing the sector, and the solutions (including improving broadband speeds and devolving skills budgets) which could help.

But the offhand reference to his own ignorance, and the implication that it would be seen as attractive by this particular audience, implies that Goldsmith, and other politicians like him, haven’t moved on since the 90s. The comment seemed designed to say: “Oh, I don't know about that - I'll leave it to the geeks like you!"

This is bad enough from a mayoral hopeful.  But on the same day, the Intelligence and Security Committee of Parliament filed its report on the Draft Investigatory Powers Bill, the legislation drafted by the Home Office which will define how and how far the government and secret services can pry into our digital communications. Throughout, there's the sense that the ISC doesn't think the MPs behind the bill had a firm grasp on the issues at hand. Words like "inconsistent" and "lacking in clarity" pop up again and again. In one section, the authors note:

"While the issues under consideration are undoubtedly complex, we are nevertheless concerned that thus far the Government has missed the opportunity to provide the clarity and assurance which is badly needed."

The report joins criticism from other directions, including those raised by Internet Service Providers last year, that the bill's writers didn't appear to know much about digital communications at all, much less the issues surrounding encryption of personal messages.

One good example: the bill calls for the collection of "internet connection records", the digital equivalent of phone call records, which show the domains visited by internet users but not their content. But it turns out these records don't exist in this form: the bill actually invented both the phrase and the concept. As one provider commented at the time, anyone in favour of their collection "do not understand how the Internet works". 

Politicians have a long and colourful history of taking on topics - even ministerial posts - in fields they know little to nothing about. This, in itself, is a problem. But politicians themselves are often the people extolling importance of technology, especially to the British economy - which makes their own lack of knowledge particularly grating. No politician would feel comfortable admitting a lack of knowledge, on, say, economics. I can’t imagine Goldsmith guffawing "Oh, the deficit?  That's all Greek to me!"  over dinner with Cameron. 

The mayoral candidates on stage at the DebateTech hustings this week were eager to agree that tech is London’s fastest growing industry, but could do little more than bleat the words “tech hub” with fear in their eyes that someone might ask them what exactly that meant. (A notable exception was Green candidate Sian Berry, who has actually worked for a tech start-up.) It was telling that all were particularly keen on improving internet speeds -  probably because this is something they do have day-to-day engagement with. Just don't ask them how to go about doing it.

The existence of organisations like Tech London Advocates, the industry group which co-organised the hustings, is important, and can go some way towards educating the future mayor on the issues the industry faces. But the technology and information sectors have been responsible for 30 per cent of job growth in the capital since 2009 - we can't afford to have a mayor who blanches at the mention of code. 

If we’re to believe the politicians themselves, with all their talk of coding camps and skills incubators and teaching the elderly to email, we need a political sphere where boasting that you're not "techy" isn’t cool or funny - it’s just kind of embarrassing. 

Barbara Speed is a technology and digital culture writer at the New Statesman and a staff writer at CityMetric.