Rajiv Sethi discusses James Tobin's "four distinct conceptions of financial market efficiency," particularly his notion of functional efficiency"
James Tobin's Hirsch Lecture, by Rajiv Sethi: James Tobin's Fred Hirsch Memorial Lecture "On the Efficiency of the Financial System" was originally published in a 1984 issue of the Lloyds Bank Review, and republished three years later in a collection of his writings. Willem Buiter discussed the essay at some length about a year ago in a provocative post dealing with the regulation of derivatives. Both the original essay and Buiter's discussion of it remain well worth reading today as guides to the broad principles that ought to underlie financial market reform.
In his essay, Tobin considers four distinct conceptions of financial market efficiency:
Efficiency has several different meanings: first, a market is 'efficient' if it is on average impossible to gain from trading on the basis of generally available public information... Efficiency in this meaning I call information arbitrage efficiency.
A second and deeper meaning is the following: a market in a financial asset is efficient if if its valuations reflect accurately the future payments to which the asset gives title... I call this concept fundamental valuation efficiency.
Third, a system of financial markets is efficient if it enables economic agents to insure for themselves deliveries of goods and services in all future contingencies, either by surrendering some of their own resources now or by contracting to deliver them in specified future contingencies... I call efficiency in this Arrow-Debreu sense full insurance efficiency.
The fourth concept relates more concretely to the economic functions of the financial industries... These include: the pooling of risks and their allocation to those most able and willing to bear them... the facilitation of transactions by providing mechanisms and networks of payments; the mobilization of saving for investments in physical and human capital... and the allocation of saving to to their more socially productive uses. I call efficiency in these respects functional efficiency.
The first two criteria correspond, respectively, to weak and strong versions of the efficient markets hypothesis. Tobin argues that the weak form is generally satisfied on the grounds that "actively managed portfolios, allowance made for transactions costs, do not beat the market." He notes, however that efficiency in the second (strong form) sense is "by no means implied" by this, and that "market speculation multiplies several fold the underlying fundamental variability of dividends and earnings."
My own view of the matter (expressed in an earlier post) is that such a neat separation of these two concepts of efficiency is too limiting: endogenous variations in the composition of trading strategies result in alternating periods of high and low volatility. Nevertheless, as an approximate view of market efficiency over long horizons, I feel that Tobin's characterization is about right.
Full insurance efficiency requires complete markets in state contingent claims. This is a theoretical ideal that is impossible to attain in practice for a variety of reasons: the real resource costs of contracting, the thinness of potential markets for exotic contingent claims, and the difficulty of dispute resolution. Nevertheless, Tobin argues for the introduction of new assets that insure against major contingencies such as inflation, and securities of this kind have indeed been introduced since his essay was published.
Finally, Tobin turns to functional efficiency, and this is where he expresses greatest concern:What is clear that very little of the work done by the securities industry, as gauged by the volume of market activity, has to do with the financing of real investment in any very direct way. Likewise, those markets have very little to do, in aggregate, with the translation of the saving of households into corporate business investment. That process occurs mainly outside the market, as retention of earnings gradually and irregularly augments the value of equity shares...
I confess to an uneasy Physiocratic suspicion, perhaps unbecoming in an academic, that we are throwing more and more of our resources, including the cream of our youth, into financial activities remote from the production of goods and services, into activities that generate high private rewards disproportionate to their social productivity. I suspect that the immense power of the computer is being harnessed to this 'paper economy', not to do the same transactions more economically but to balloon the quantity and variety of financial exchanges. For this reason perhaps, high technology has so far yielded disappointing results in economy-wide productivity. I fear that, as Keynes saw even in his day, the advantages of the liquidity and negotiability of financial instruments come at the cost of facilitation nth-degree speculation which is short sighted and inefficient...Arrow and Debreu did not have continuous sequential trading in mind; when that occurs, as Keynes noted, it attracts short-horizon speculators and middlemen, and distorts or dilutes the influence of fundamentals on prices. I suspect that Keynes was right to suggest that we should provide greater deterrents to transient holdings of financial instruments and larger rewards for long-term investors.
Recall that these passages were published in 1984; the financial sector has since been transformed beyond recognition. Buiter argues that Tobin's concerns about functional efficiency are more valid today than they have ever been, and is particularly concerned with derivatives contacts involving directional bets by both parties to the transaction:[Since] derivatives trading is not costless, scarce skilled resources are diverted to what are not even games of pure redistribution. Instead these resources are diverted towards games involving the redistribution of a social pie that shrinks as more players enter the game.
The inefficient redistribution of risk that can be the by-product of the creation of new derivatives markets and their inadequate regulation can also affect the real economy through an increase in the scope and severity of defaults. Defaults, insolvency and bankruptcy are key components of a market economy based on property rights. There involve more than a redistribution of property rights (both income and control rights). They also destroy real resources. The zero-sum redistribution characteristic of derivatives contracts in a frictionless world becomes a negative-sum redistribution when default and insolvency is involved. There is a fundamental asymmetry in the market game between winners and losers: there is no such thing as super-solvency for winners. But there is such a thing as insolvency for losers, if the losses are large enough.The easiest solution to this churning problem would be to restrict derivatives trading to insurance, pure and simple. The party purchasing the insurance should be able to demonstrate an insurable interest. [Credit Default Swaps] could only be bought and sold in combination with a matching amount of the underlying security.
The debate over naked credit default swaps is contentious and continues to rage. While market liquidity and stability have been central themes in this debate to date, it might be useful also to view the issue through the lens of functional efficiency. More generally, we ought to be asking whether Tobin was right to be concerned about the size of the financial sector in his day, and whether its dramatic growth over the couple of decades since then has been functional or dysfunctional on balance.