Feb 7 JDN 2459253

No doubt by now you’ve heard about the recent bubble in GameStop stock that triggered several trading stops, nearly destroyed a hedge fund, and launched a thousand memes. What really strikes me about this whole thing is how ordinary it is: This is basically the sort of thing that happens in our financial markets all the time. So why are so many people suddenly paying so much attention to it?

There are a few important ways this is unusual: Most importantly, the bubble was triggered by a large number of middle-class people investing small amounts, rather than by a handful of billionaires or hedge funds. It’s also more explicitly collusive than usual, with public statements in writing about what stocks are being manipulated rather than hushed whispers between executives at golf courses. Partly as a consequence of these, the response from the government and the financial industry has been quite different as well, trying to halt trading and block transactions in a way that they would never do if the crisis had been caused by large financial institutions.

If you’re interested in the technical details of what happened, what a short squeeze is and how it can make a hedge fund lose enormous amounts of money unexpectedly, I recommend this summary by KQED. But the gist of it is simple enough: Melvin Capital placed huge bets that GameStop stock would fall in price, and a coalition of middle-class traders coordinated on Reddit to screw them over by buying a bunch of GameStop stock and driving up the price. It worked, and now Melvin Capital lost something on the order of $3-5 billion in just a few days.

The particular kind of bet they placed is called a short, and it’s a completely routine practice on Wall Street despite the fact that I could never quite understand why it is a thing that should be allowed.

The essence of a short is quite simple: When you short, you are selling something you don’t own. You “borrow” it (it isn’t really even borrowing), and then sell it to someone else, promising to buy it back and return it to where you borrowed it from at some point in the future. This amounts to a bet that the price will decline, so that the price at which you buy it is lower than the price at which you sold it.

Doesn’t that seem like an odd thing to be allowed to do? Normally you can’t sell something you have merely borrowed. I can’t borrow a car and then sell it; car title in fact exists precisely to prevent this from happening. If I were to borrow your coat and then sell it to a thrift store, I’d have committed larceny. It’s really quite immaterial whether I plan to buy it back afterward; in general we do not allow people to sell things that they do not own.

Now perhaps the problem is that when I borrow your coat or your car, you expect me to return that precise object—not a similar coat or a car of equivalent Blue Book value, but your coat or your car. When I borrow a share of GameStop stock, no one really cares whether it is that specific share which I return—indeed, it would be almost impossible to even know whether it was. So in that way it’s a bit like borrowing money: If I borrow $20 from you, you don’t expect me to pay back that precise $20 bill. Indeed you’d be shocked if I did, since presumably I borrowed it in order to spend it or invest it, so how would I ever get it back?

But you also don’t sell money, generally speaking. Yes, there are currency exchanges and money-market accounts; but these are rather exceptional cases. In general, money is not bought and sold the way coats or cars are.

What about consumable commodities? You probably don’t care too much about any particular banana, sandwich, or gallon of gasoline. Perhaps in some circumstances we might “loan” someone a gallon of gasoline, intending them to repay us at some later time with a different gallon of gasoline. But far more likely, I think, would be simply giving a friend a gallon of gasoline and then not expecting any particular repayment except perhaps a vague offer of providing a similar favor in the future. I have in fact heard someone say the sentence “Can I borrow your sandwich?”, but it felt very odd when I heard it. (Indeed, I responded something like, “No, you can keep it.”)

And in order to actually be shorting gasoline (which is a thing that you, too, can do, perhaps even right now, if you have a margin account on a commodities exchange), it isn’t enough to borrow a gallon with the expectation of repaying a different gallon; you must also sell that gallon you borrowed. And now it seems very odd indeed to say to a friend, “Hey, can I borrow a gallon of gasoline so that I can sell it to someone for a profit?”

The usual arguments for why shorting should be allowed are much like the arguments for exotic financial instruments in general: “Increase liquidity”, “promote efficient markets”. These arguments are so general and so ubiquitous that they essentially amount to the strongest form of laissez-faire: Whatever Wall Street bankers feel like doing is fine and good and part of what makes American capitalism great.

In fact, I was never quite clear why margin accounts are something we decided to allow; margin trading is inherently high-leverage and thus inherently high-risk. Borrowing money in order to arbitrage financial assets doesn’t just seem like a very risky thing to do, it has been one way or another implicated in virtually every financial crisis that has ever occurred. It would be an exaggeration to say that leveraged arbitrage is the one single cause of financial crises, but it would be a shockingly small exaggeration. I think it absolutely is fair to say that if leveraged arbitrage did not exist, financial crises would be far rarer and further between.

Indeed, I am increasingly dubious of the whole idea of allowing arbitrage in general. Some amount of arbitrage may be unavoidable; there may always be people people who see that prices are different for the same item in two different markets, and then exploit that difference before anyone can stop them. But this is a bit like saying that theft is probably inevitable: Yes, every human society that has had a system of property ownership (which is most of them—even communal hunter-gatherers have rules about personal property), has had some amount of theft. That doesn’t mean there is nothing we can do to reduce theft, or that we should simply allow theft wherever it occurs.

The moral argument against arbitrage is straightforward enough: You’re not doing anything. No good is produced; no service is provided. You are making money without actually contributing any real value to anyone. You just make money by having money. This is what people in the Middle Ages found suspicious about lending money at interest; but lending money actually is doing something—sometimes people need more money than they have, and lending it to them is providing a useful service for which you deserve some compensation.

A common argument economists make is that arbitrage will make prices more “efficient”, but when you ask them what they mean by “efficient”, the answer they give is that it removes arbitrage opportunities! So the good thing about arbitrage is that it stops you from doing more arbitrage?

And what if it doesn’t stop you? Many of the ways to exploit price gaps (particularly the simplest ones like “where it’s cheap, buy it; where it’s expensive, sell it”) will automatically close those gaps, but it’s not at all clear to me that all the ways to exploit price gaps will necessarily do so. And even if it’s a small minority of market manipulation strategies that exploit gaps without closing them, those are precisely the strategies that will be most profitable in the long run, because they don’t undermine their own success. Then, left to their own devices, markets will evolve to use such strategies more and more, because those are the strategies that work.

That is, in order for arbitrage to be beneficial, it must always be beneficial; there must be no way to exploit price gaps without inevitably closing those price gaps. If that is not the case, then evolutionary pressure will push more and more of the financial system toward using methods of arbitrage that don’t close gaps—or even exacerbate them. And indeed, when you look at how ludicrously volatile and crisis-prone our financial system has become, it sure looks an awful lot like an evolutionary equilibrium where harmful arbitrage strategies have evolved to dominate.

A world where arbitrage actually led to efficient pricing would be a world where the S&P 500 rises a steady 0.02% per day, each and every day. Maybe you’d see a big move when there was actually a major event, like the start of a war or the invention of a vaccine for a pandemic. You’d probably see a jump up or down of a percentage point or two with each quarterly Fed announcement. But daily moves of even five or six percentage points would be a very rare occurrence—because the real expected long-run aggregate value of the 500 largest publicly-traded corporations in America is what the S&P 500 is supposed to represent, and that is not a number that should change very much very often. The fact that I couldn’t really tell you what that number is without multi-trillion-dollar error bars is so much the worse for anyone who thinks that financial markets can somehow get it exactly right every minute of every day.

Moreover, it’s not hard to imagine how we might close price gaps without simply allowing people to exploit them. There could be a bunch of economists at the Federal Reserve whose job it is to locate markets where there are arbitrage opportunities, and then a bundle of government funds that they can allocate to buying and selling assets in order to close those price gaps. Any profits made are received by the treasury; any losses taken are borne by the treasury. The economists would get paid a comfortable salary, and perhaps get bonuses based on doing a good job in closing large or important price gaps; but there is no need to give them even a substantial fraction of the proceeds, much less all of it. This is already how our money supply is managed, and it works quite well, indeed obviously much better than an alternative with “skin in the game”: Can you imagine the dystopian nightmare we’d live in if the Chair of the Federal Reserve actually received even a 1% share of the US money supply? (Actually I think that’s basically what happened in Zimbabwe: The people who decided how much money to print got to keep a chunk of the money that was printed.)

I don’t actually think this GameStop bubble is all that important in itself. A decade from now, it may be no more memorable than Left Shark or the Macarena. But what is really striking about it is how little it differs from business-as-usual on Wall Street. The fact that a few million Redditors can gather together to buy a stock “for the lulz” or to “stick it to the Man” and thereby bring hedge funds to their knees is not such a big deal in itself, but it is symptomatic of much deeper structural flaws in our financial system.