Paul Krugman has a nice column today warning us that the recent record highs in the stock market indices don’t mean that happy days are here again. While I agree with much of what he says, I don’t agree with all of it, so let me try to sort out what I think is right and what I think may not be right.
Like most economists, I don’t usually have much to say about stocks. Stocks are even more susceptible than other markets to popular delusions and the madness of crowds, and stock prices generally have a lot less to do with the state of the economy or its future prospects than many people believe.
I think that’s generally right. The efficient market hypothesis (EMH) is at best misleading in positing that market prices are determined by solid fundamentals. What does it mean for fundamentals to be solid? It means that the fundamentals remain what they are independent of what people think they are. But if fundamentals themselves depend on opinions, the idea that values are determined by fundamentals is a snare and a delusion. So the fundamental idea on which the EMH is premised that there are fundamentals is itself fundamentally wrong. Fundamentals are no more than conjectures and psychologically flimsy perceptions, and individual perceptions are themselves very much influenced by how other people perceive the world and their perceptions. That’s why fads are contagious and bubbles can arise. But because fundamentals are nothing but opinions, expectations can be self-fulfilling. So it is possible for some ex ante bubbles to wind up being justified ex post, but only because expectations can be self-fulfilling.
Still, we shouldn’t completely ignore stock prices. The fact that the major averages have lately been hitting new highs — the Dow has risen 177 percent from its low point in March 2009 — is newsworthy and noteworthy. What are those Wall Street indexes telling us?
Stock prices are in fact governed by expectations, but expectations may or may not be rational, where a rational expectation is an expectation that could actually be realized in some possible state of the world.
The answer, I’d suggest, isn’t entirely positive. In fact, in some ways the stock market’s gains reflect economic weaknesses, not strengths. And understanding how that works may help us make sense of the troubling state our economy is in. . . .
The truth . . . is that there are three big points of slippage between stock prices and the success of the economy in general. First, stock prices reflect profits, not overall incomes. Second, they also reflect the availability of other investment opportunities — or the lack thereof. Finally, the relationship between stock prices and real investment that expands the economy’s capacity has gotten very tenuous.
To put this into the slightly different language of basic financial theory, stock prices reflect the expected future cash flows from owning shares of publicly traded corporations. So stock prices reflect the net value of the tangible and intangible capital assets of these corporations. The public valuations of those assets reflected in stock prices reflect expectations about the future income streams associated with those assets, but those expected future income streams must be discounted so that they can be expressed as a present value. The rate at which future income streams are discounted into the present represents what Krugman calls “the availability of other investment opportunities.” If lots of good investment opportunities are available, then future income streams will be discounted at a higher rate than if there aren’t so many good investment opportunities. In theory the discount rate at which future income streams are discounted would reflect the rate of return corresponding to the marginal investment opportunities that are on the verge of being adopted or abandoned, because they just break even. What Krugman means by the tenuous relationship between stock prices and real investment that expands the economy’ capacity will have to be considered below.
Krugman maintains that, over the past two decades, even though the economy as a whole has not done all that well, stock prices have increased a lot, because the share of capital in total GDP has increased at the expense of labor. He also points out that the low — even negative — real interest rates on government bonds are indicative of the poor opportunities now available (at the margin) to investors.
And these days those options [“for converting money today into income tomorrow”] are pretty poor, with interest rates on long-term government bonds not only very low by historical standards but zero or negative once you adjust for inflation. So investors are willing to pay a lot for future income, hence high stock prices for any given level of profits.
Two points should be noted here. First, scare talk about low interest rates causing bubbles because investors search for yield is nonsense. Even in a fundamentalist EMH universe, a deterioration of marginal investment opportunities causing a drop in the real interest rate will, for given expectations of future income streams, imply that the present value of the assets generating those streams would rise. Rising asset prices in such circumstances are totally rational, which is exactly what bubbles are not. Second, the low interest rates on long-term government bonds are not the cause of poor investment opportunities but the result of poor investment opportunities. Krugman certainly understands that, but many of his readers might not.
But why are long-term interest rates so low? As I argued in my last column, the answer is basically weakness in investment spending, despite low short-term interest rates, which suggests that those rates will have to stay low for a long time.
Again, this seems inexactly worded. Weakness in investment spending is a symptom not a cause, so we are back to where we started from. At the margin, there are no attractive investment opportunities. The mystery deepens:
This may seem, however, to present a paradox. If the private sector doesn’t see itself as having a lot of good investment opportunities, how can profits be so high? The answer, I’d suggest, is that these days profits often seem to bear little relationship to investment in new capacity. Instead, profits come from some kind of market power — brand position, the advantages of an established network, or good old-fashioned monopoly. And companies making profits from such power can simultaneously have high stock prices and little reason to spend.
Why do profits bear only a weak relationship to investment in new capacity? Krugman suggests that the cause is that rising profits are due to the exercise of market power, firms increasing profits not by increasing output, but by restricting output to raise prices (not necessarily in absolute terms but relative to costs). This is a kind of microeconomic explanation of a macroeconomic phenomenon, which does not necessarily make it wrong, but it is a somewhat anomalous argument for a Keynesian. Be that as it may, to be credible such an argument must explain how the share of corporate profits in total income has been able to grow steadily for nearly twenty years. What would account for a steady economy-wide increase in the market power of corporations lasting for two decades?
Consider the fact that the three most valuable companies in America are Apple, Google and Microsoft. None of the three spends large sums on bricks and mortar. In fact, all three are sitting on huge reserves of cash. When interest rates go down, they don’t have much incentive to spend more on expanding their businesses; they just keep raking in earnings, and the public becomes willing to pay more for a piece of those earnings.
Krugman’s example suggests that the continuing increase in market power, if that is what has been happening, has been structural. By structural I mean that much of the growth in the economy over the past two decades has been in sectors characterized by strong network effects or aggressive enforcement of intellectual property rights. Network effects and strong intellectual property rights tend to create, enhance, and entrench market power, supporting very large gaps between prices and variable costs, which is the standard metric for identifying exercises of market power. The nature of what these companies offer consumers is such that their marginal cost of production is very low, so that reducing price and expanding output would not require a substantial increase in their demand for inputs (at least compared to other industries with higher marginal costs), but would cause a big loss of profit.
But I would suggest looking at the problem from a different perspective, using the distinction between two kinds of capital investment proposed by Ralph Hawtrey. One kind of investment is capital deepening, which involves an increase in the capital intensity of production, the idea being to reduce the cost of production by installing new or better equipment to economize on other inputs (usually labor); the other kind of investment is capital widening, which involves an increase in the scale of output but not in capital intensity, for example building a new plant or expanding an existing one. Capital deepening tends to reduce the demand for labor while capital widening tends to increase it.
More of the investment now being undertaken may be of the capital-deepening sort than has been true historically. Aside from the structural shifts mentioned above, the reduction in capital-widening investment may be the result of declining optimism by businesses in their projections about future demand for their products, making capital-widening investments seem less profitable. For the economy as a whole, a decline in optimism about future demand may turn out to be self-fulfilling. Thus, an increasing share of total investment has become capital-deepening and a declining share capital-widening. But for the economy as a whole, this self-fulfilling pessimism implies that total investment declines. The question is whether monetary (or fiscal) policy could now do anything to increase expectations of future demand sufficiently to induce an self-fulfilling increase in optimism and in capital-widening investment.