Streetwise Professor

September 16, 2011

One More Time: Commodities are Different than Assets

Filed under: Commodities,Derivatives,Economics,Energy,Politics,Regulation — The Professor @ 6:46 pm

Interesting to note that Ken Singleton and I are commonly being used to personify contending sides in the commodity speculation debate.  One example is this piece from the FT on Wednesday.

Before going into substance, I need to set the record straight.  Javier Blas is flatly incorrect to say that I criticized “the CFTC’s decision to invite academics who mainly defended only one point of view.”  Flatly incorrect.  I have never said that either publicly or privately, and I defy Mr. Blas to prove otherwise.

Indeed, I was invited, so I know the statement to be untrue and I would not make it becuase (a) I just wouldn’t, and (b) I’m not so foolish as to make a statement that could easily be proven wrong.   I decided not to attend the event for a variety of reasons, most of them personal.

So, a retraction and correction is warranted (though I’m not holding my breath).

Now that’s out of the way, let me revisit one more time why the Singleton paper is being grossly misinterpreted, though not by Ken (at least in ear/eyeshot of me).

To recapitulate, Singleton finds that a measure of index fund participation helps predict future returns on oil futures positions.   This measure has serious, serious problems, as Scott Irwin and Dwight Sanders have shown.  Singleton has acknowledged some of the problems.  But that still leaves a puzzle, as why would a very noisy measure of speculative participation have predictive power?  But I’ll leave that puzzle aside and take as given that speculation leads prices.

The question is: why?  Does this mean that speculation has distorted prices?

In a rather stinging response to Singleton, the IEA does a nice job of summarizing my views as to why it does not necessarily support this conclusion, and could support the exact opposite one:

Finally, as suggested by the University of Houston’s Craig Pirrong in his blog, suppose that Professor Singleton’s findings do indicate that excess returns on crude oil futures are predictable, conditional on measures of speculative activity. Nonetheless, such a predictability of returns would not imply that speculation has distorted prices. Rather, predictability is the result of market frictions that might create hedging demand, leading to an increase in the risk premium. Professor Pirrong suggests that, in such circumstances, speculative positions can predict changes in futures prices. To prevent the predictability  of returns, it might be advisable to reduce constraints on the flow of speculative investment to  commodity markets, rather than limiting them.

(The entire IEA piece is worth reading.)

Singleton advances another argument–and it is only that, because his evidence cannot distinguish his explanation from that just advanced–based on various behavioral finance/learning stories.  There are indeed asset pricing models in which investor learning can lead to self-reinforcing price movements.  The key phrase here is “asset pricing models.”  The key question is whether such asset pricing models are applicable to commodities.

I am highly, highly skeptical.  Assume for sake of argument that speculative activity in a commodity derivatives market has distorted the price of the commodity; convergence implies that if nearby futures prices are indeed distorted, physical prices have to be distorted too.

Millions–and in some cases billions–of individual consumers, and myriad producers, face these prices.  If these producers and consumers are not playing the same learning game that is going on in the futures market, the price distortion will affect their production and consumption decisions.  All else equal, if speculators cause the price to be too high, consumption will be depressed, and production will increased.  This will lead to an accumulation of inventories.  If the price distortion is large, the inventory accumulation is likely to be large.

Now, there are circumstances in which it may be difficult to detect empirically the inventory accumulation.  If supply and demand are extremely–extremely–inelastic, large price moves may result in small inventory changes that are hard to detect in the noisy stock data that are available for some commodities.  Moreover, all else may not be equal.  As Singleton (perhaps cleverly) notes, my research shows that a decline in fundamental uncertainty could lead to a decline in inventory that masks the speculation-induced change.  (Although more plausibly, higher fundamental volatility leads to greater speculation, which would lead to an increase in inventory that could be blamed on speculative price distortions.)

But there are historical episodes–like the Hunts in silver and government price-support programs–in which price distortions have been associated with huge accumulations of inventory.  Those claiming speculative distortion need to provide a credible explanation whenever an alleged price bubble is not accompanied by a rise in inventories.  It can happen, but it’s unlikely–so show me how.

So, for the Singleton story to work, it has to be the case that consumers and producers–or at least a big chunk of them–are playing the same learning game as the investors.  I find this wildly implausible, particularly for consumers.  Would consumers really buy more gasoline today–gasoline which they are going to consume, not store in anticipation of profiting from price appreciation–for speculative reasons because prices have been trending up?  Really? (Perhaps you could argue that they would engage in intertemporal substitution, but this also stretches credulity.)  It might be somewhat more plausible that suppliers would not produce more today in response to a speculative price bubble in anticipation that they can sell at a higher price in the future.

These stories–and they are just that–are not logically impossible, but they are just implausible, to me anyways.  The consumer side is particularly implausible.  To emphasize: most consumers of gasoline or copper or corn or whatever cannot store the commodity, and hence cannot earn a speculative profit.  Thus, they should respond parametrically to prices, and respond to higher prices by reducing consumption.  The decline in consumption in markets (like the US) where consumers are subject to price changes (because there are no price controls or subsidies) during the oil price spike of 2008 supports this view.  So price distortions should lead to inventory accumulation.

This is an excellent illustration of why commodities are a good place to test theories of speculative distortion.  The speculators may play their games in the financial markets, but if they affect prices, consumers and producers who don’t play the game alter their behavior.  Looking for evidence of behavioral changes–consumption and production changes–is a great way to detect price distortions.  That is not possible in asset markets.  Consumers and producers are canaries in the coal mine.

Which all means that to persuade, Singleton, and those who are using his paper to say Eureka!, need to provide a plausible explanation of how learning/behavioral finance effects change the behavior of producers and consumers in ways that what would mean that price distortions do not lead to noticeable changes in quantities like inventory.  That is, he points to models of asset markets in which there are no consumers; to make a realistic and testable model, you would need to include producers and consumers as well–not just demand for a stock of assets, but flow demand and supply.

One last thing.   The Singleton paper has “boom and bust” in the title, and many behavioral finance/learning models predict boom and bust patterns in speculative prices.  There was a boom and bust in oil prices and other commodity prices–but the bust in 2008 was not plausibly the kind of speculative bubble bursting that occurs in the models.  It was definitely driven by a huge collapse in demand resulting from the financial crisis.  Thus the “bust” part of the price movements should not be used as evidence in favor of the theory.  Instead, it fits far better a fundamentals-based story.  As I told many reporters as prices peaked in summer 2008, when they asked what would bring down prices: be careful what you ask for.  A major recession would be the most likely cause of a big price decline.  That’s what happened–not the bursting of a speculative bubble.

Relatedly.  Prices that positively cannot be driven by asset pricing bubbles–because they are are definitively not assets–boom and bust.  During the same period that oil prices were booming and then busting, shipping rates were doing the same thing.  Space on a ship is not an asset.  It is not storable; you use it or lose it.  You can speculate on the price of the ship, but the price of the services of the ship cannot be subject to asset pricing bubbles–because these services are not an asset.  The spike and thudding collapse of shipping rates in 2007-early 2009 is indicative of a rise and fall in the demand for commodities (which are transported by ship), and cannot be explained by speculative distortion induced by learning, etc. Put differently, booms and busts occur in markets in which asset price bubbles are impossible.

To summarize.  1. Singleton’s results are perfectly consistent with rational pricing, no speculative distortions, and financial market frictions.  2.  The conditions that would reconcile the kind of learning/behavioral finance model that would be necessary to explain the lack of inventory accumulation are highly implausible.  If somebody wants to tell a more convincing story about commodity price bubbles, it is necessary to do more than just genuflect to models devised to explain things like the dot-com bubble.   You have to create a model that includes flow demand and supply, and derive testable implications of investor/speculator learning or irrationality for quantities produced, consumed, and stored.   Only then will it even be remotely possible to determine the real implications of these learning models for commodities.

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1 Comment »

  1. I understand that index funds are almost exclusively long in commodity markets. If that is true then how can the massive increase in demand from hundreds of billions of dollars in indexes not influence prices in the market? It’s the first time I have heard free market believers argue that an increase in demand does not influence prices…

    Comment by Dave — September 19, 2011 @ 8:23 am

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