Equity Markets, the Money Market, and Long-Run Monetary Neutrality

This paper outlines a process for teaching long-run neutrality of money, drawing an analogy between equity markets and the money market. The key points in the discussion include the following: (1) What is the price of money? (2) Why does the long-run demand for money trace out a rectangular hyperbola? (3) Why does the slow adjustment of goods and service prices to changes in the stock of money lead to a different short-run demand for money? and (4) Why does a successful currency reform generate similar short-run movements in the price of money as movements in equity share prices after a change in the supply of shares? I have used this approach successfully for over 30 years at all levels, wherever I need to discuss the money market in a macroeconomic model.

Asset Pricing with Heterogeneous Agents, Incomplete Markets and Trading Constraints

The consumption capital asset pricing model is the standard economic model used to capture stock market behavior. However, empirical tests have pointed out to its inability to account quantitatively for the high average rate of return and volatility of stocks over time for plausible parameter values. Recent research has suggested that the consumption of stockholders is more strongly correlated with the performance of the stock market than the consumption of non-stockholders. We model two types of agents, non-stockholders with standard preferences and stock holders with preferences that incorporate elements of the prospect theory developed by Kahneman and Tversky (1979). In addition to consumption, stockholders consider fluctuations in their financial wealth explicitly when making decisions. Data from the Panel Study of Income Dynamics are used to calibrate the labor income processes of the two types of agents. Each agent faces idiosyncratic shocks to his labor income as well as aggregate shocks to the per-share dividend but markets are incomplete and agents cannot hedge consumption risks completely. In addition, consumers face both borrowing and short-sale constraints. Our results show that in equilibrium, agents hold different portfolios. Our model is able to generate a time-varying risk premium of about 5.5% while maintaining a low risk free rate, thus suggesting a plausible explanation for the equity premium puzzle reported by Mehra and Prescott (1985).