Equilibrium valuation of illiquid assets

Summary. We develop an equilibrium model of illiquid asset valuation based on search and matching. We propose several measures of illiquidity and show how these measures behave. We also show that the equilibrium amount of search may be less than, equal to or greater than the amount of search that is socially optimal. Finally, we show that excess returns on illiquid assets are fair games if returns are defined to include the appropriate shadow prices. Received: June 25, 2000; revised version: October 24, 2000     

The importance of fear: investor sentiment and stock market returns

The presence of investor sentiment pushes asset prices away from the equilibrium level justified by underlying fundamentals. While sentiment is not directly observable, identifying appropriate proxies and, quantifying the impact of sentiment on asset prices is an important topic. Asset prices that do not appropriately reflect fundamental values may result in inefficient allocation of capital – impacting portfolio allocation decisions and the cost of capital. Utilizing a number of sentiment proxies, over the period 1990–2015, we demonstrate a strong relationship between investor sentiment and stock returns that is consistent with theoretical explanations of sentiment. We determine that implied volatility index (VIX) is the preferred measure of sentiment in terms of improving model fit and adding explanatory power. Causality tests suggest that investor fear (VIX) drives returns across firm-size and value, and also across industry. We also illustrate that firms that are more subjective to value, or face limits to arbitrage, such as small-cap stocks, or those in the business equipment (technology) or telecoms industry, are most responsive to changes investor sentiment. Finally, we demonstrate that sentiment has a greater influence on market returns during recession, when sentiment is at its lowest ebb, and this is particularly true for those stocks most susceptible to speculative demand.     

Asset price volatility in a nonconvex general equilibrium model

Summary. Asset prices and returns are known to vary significantly more than␣output or aggregate consumption growth, and an order of magnitude in excess of what is justified by innovations to fundamentals. We study excess price volatility in a lifecycle economy with two assets (claims on capital and␣a public debt bubble), heterogeneous agents, and increasing returns to financial intermediation. We show that a relatively modest nonconvexity generates a set valued equilibrium correspondence in asset prices, with two␣stable branches. Price volatility is the outcome of an equilibrium selection mechanism, which mixes adaptive learning with “noise”, and alternates stochastically between the two stable branches of the price correspondence. Received: March 19, 1998; revised version: June 2, 1998     

Product differentiation,prices, and market structure

We examine the effect of cost reductions and advertising on equilibrium prices and the equilibrium market shares. Our equilibrium has the following characteristics; the aggregate demand is the integral of individual demand over consumers, goods are differentiated in the sense of Novshek and Sonnenschein (1979), production functions are constant returns to scale.Cost reductions of a firm, which are due to R&D activity of the firm, lead to declines of equilibrium prices. Advertising of a firm, which is supposed to influence consumers' preferences in favor of the firm, cannot necessarily cause equilibrium prices to go up; one firm can raise its prices, but the other cannot. Contrary to our intuition, cost reductions cannot always enable a firm to capture a larger share.     

Sraffa and the Assumption of Constant Returns to Scale: A Critique of Samuelson and Etula

In a recent paper Samuelson and Etula claim to have providedthree examples of the presence of a constant returns to scaleassumption in Sraffa's Production of Commodities. The presentpaper is a refutation of their interpretation of Sraffa's propositions.It shows that they mistakenly take Sraffa's logical propositionsfor empirical propositions. This article also provides evidenceto refute Samuelson's hypothesis that Sraffa consistently confusedthe concept of Marshallian "constant cost" with the generalequilibrium concept of "constant returns to scale". The paperalso argues that Sraffa's prices are not necessarily "equilibrium"prices, and that it is not true that Sraffa maintained thatchanges in demand had no impact on prices; his position appearsrather to be that the impact of demand on prices is unpredictable.     

Asset price fluctuations without aggregate shocks

We analyze the pricing of a productive asset in a class of dynamic exchange economies with heterogeneous, infinitely-lived agents, and self-enforcing intertemporal trades. Individual incomes fluctuate and are correlated; preferences, dividends and aggregate income are fixed. Almost all economies in this class have a unique stationary Markovian equilibrium with fluctuations in asset prices. As the set of unrationed households changes over time and states, excess demand functions shift, asset returns fluctuate, and some households are shut out of asset markets. Examples suggest that the amplitude of these movements is negatively correlated with the productivity of the asset and with the penalty for default.     

THE INFLATION AND SUPPLY SIDE CONSEQUENCES OF DEMAND SIDE SHOCKS*

This paper outlines a small general equilibrium model derived under the assumptions of imperfect competition and non-constant returns to scale Cobb-Douglas technology. The model is used to simulate the short-run supply side effects of a demand shock. The simulation results reveal that demand shocks lower prices and result in positive supply side effects, which in turn strengthen the positive demand side effects on unemployment.     

International asset prices and portfolio choices under Bayesian learning

We calculate equilibrium asset prices and portfolio choices from a two-country OLG international asset pricing model under the assumption that investors are on a Bayesian learning path. Investors from both countries receive identical information flows, but domestic investors start off with less precise priors concerning foreign fundamentals. Learning is shown to produce first-order effects on the properties of asset prices, in the form of increased equity returns, volatility clustering, and time-varying correlations across national stock markets. Moreover, on a learning path, estimation risk generates portfolio biases similar to those observed empirically, i.e. a strong preference towards domestic securities and excessive turnover in foreign securities. These findings are robust to changes in prior beliefs, the calibration of initial information asymmetries, and the parameterization of the model. We use real GDP data for the US and Europe to calibrate the model and show that in the event of a financial liberalization during the 1970s, high excess returns, time-varying volatility, substantial home bias, and excess turnover should have been observed.     

Stability of supply function equilibria implications for daily versus hourly bids in a poolco market

We consider a supply function model of a poolco electricity market where demand varies significantly over a time horizon such as a day and also has a small responsiveness to price. Although there are equilibria yielding prices at peak that are close to Cournot prices, it is known that the wider the range of demand uncertainty the narrower the range of such supply function equilibria. Here we show that such equilibria are also typically unstable and consequently would be difficult to sustain in practice. This strengthens the results of Green and Newbery by ruling out many equilibria that have high prices. We demonstrate this result both theoretically under somewhat restrictive assumptions and also numerically using both a three-firm example system and a five-firm example system having generation capacity constraints. Hence, this reinforces the conclusion that the market outcome is significantly influenced by a requirement that offers into the poolco be consistent over the time horizon. This result contrasts with markets where bids can be changed on an hourly basis, where Cournot prices are possible outcomes. The stability analysis has important policy implications for the design of day-ahead electricity markets. The stability perspective also provides a narrowing of the equilibrium selection that strengthens empirical analysis.      

Modelling price pressure in financial markets

We present experimental evidence that, unlike traditional assumptions in economic theory, security prices do not respond to pressure from their own excess demand. Instead, prices respond to excess demand of all securities, despite the absence of a direct link between markets. We propose a model of price pressure that explains these findings. In our model, agents set order prices that reflect the marginal valuation of desired future holdings, called “aspiration levels.”In the short run, as agents encounter difficulties executing their orders, they scale back their aspiration levels. Marginal valuations, order prices, and hence, transaction prices change correspondingly. The resulting price adjustment process coincides with the Global Newton Method. The assumptions of the model as well as its empirical implications are fully borne out by the data. Our model thus provides an economic foundation for why markets appear to search for equilibrium according to Newton’s procedure.