Research Database

In empirical studies of the CAPM, it is commonly assumed that, (a) the return to the value-weighted portfolio of all stocks is a reasonable proxy for the return on the market portfolio of all assets in the economy, and (b) betas of assets remain constant over time. Under these assumptions, Fama and French (1992) find that the relation between average return and beta is flat. We argue that these two auxiliary assumptions are not reasonable. We demonstrate that when these assumptions are relaxed, the empirical support for the CAPM is very strong. When human capital is also included in measuring wealth, the CAPM is able to explain 28% of the cross sectional variation in average returns in the 100 portfolios studied by Fama and French. When, in addition, betas are allowed to vary over the business cycle, the CAPM is able to explain 57%. More important, relative size does not explain what is left unexplained after taking sampling errors into account.

This paper develops the quantitative implications of optimal fiscal policy in a business cycle model. In a stationary equilibrium the ex ante tax rate on capital income is approximately zero. There is an equivalence class of ex post capital income tax rates and bond policies that support a given allocation. Within this class the optimal ex post capital tax rates can range from being close to i.i.d. to being close to a random walk. The tax rate on labor income fluctuates very little and inherits the persistence properties of the exogenous shocks and thus there is no presumption that optimal labor tax rates follow a random walk. The welfare gains from smoothing labor tax rates and making ex ante capital income tax rates zero are small and most of the welfare gains come from an initial period of high taxation on capital income.

Since it is the dominant paradigm of the business cycle and growth literatures, the stochastic growth model has been used to test the performance of alternative numerical methods. This paper applies the finite element method to this example. I show that the method is easy to apply and, for examples such as the stochastic growth method, gives accurate solutions within a second or two on a desktop computer. I also show how inequality constraints can be handled by redefining the optimization problem with penalty functions.

We develop a model of a representative democracy in which a legislature makes collective decisions about local public goods expenditures and how they are financed. In our model of the political process legislators defer to spending requests of individual representatives, particularly committee chairmen, who tend to promote spending requests that benefit their own districts. Because legislators do not fully internalize the tax consequences of their individual spending proposals, there is a free rider problem, and as a result spending is excessively high. This leads legislators to prefer a higher level of debt to restrain excessive future spending.

We estimate a dynamic general equilibrium model of the U.S. economy that includes an explicit household production sector. We use these estimates to investigate two issues. First, we analyze how well the model accounts for aggregate fluctuations. Second, we use the model to study the effects of fiscal policy. We find household production has a significant impact, and reject a nested specification in which changes in the home production technology do not matter for market variables. The model generates very different predictions for the effects of tax changes than similar models without home production.

We show that valuing performance is equivalent to valuing a particular contingent claim on an index portfolio. In general the form of the contingent claim is not known and must be estimated. We suggest approximating the contingent claim by a series of options. We illustrate the use of our method by evaluating the performance of 130 mutual funds during the period 1968–82. We find that the relative performance rank of a fund is rather insensitive to the choice of the index, even though the actual value of the services of the portfolio manager depends on the choice of the index.

In this paper, we build a model of the transition following large-scale economic reforms that predicts both a substantial drop in output and a prolonged pause in physical investment as the initial phase of the optimal transition following the reform. We model reform as a change in policy which induces agents to close existing enterprises using old technologies of production and to open up new enterprises adopting new technologies of production. The central idea of our paper is that it is costly to close old enterprises and open new enterprises because, in doing so, information capital built up about old enterprises is lost and time must pass before information capital about new enterprises can be acquired. Thus, an acceleration of the pace of industry evolution leads in the short run to a net loss of information capital, a drop in productivity, a recession, and a fall in physical investment. We calibrate our model of industry evolution, information capital, and transition to match micro data on industry evolution in the United States and macro data from the United States, Japan, and the former communist countries of Europe. We find that the loss of information capital that accompanies a major acceleration in the pace of industry evolution in an economy leads initially to a decade of recession and a five year pause in physical investment before the benefits of reform are realized.

We find support for a negative relation between conditional expected monthly return and conditional variance of monthly return, using a GARCH-M model modified by allowing (i) seasonal patterns in volatility, (ii) positive and negative innovations to returns having different impacts on conditional volatility, and (iii) nominal interest rates to predict conditional variance. Using the modified GARCH-M model, we also show that monthly conditional volatility may not be as persistent as was thought. Positive unanticipated returns appear to result in a downward revision of the conditional volatility whereas negative unanticipated returns result in an upward revision of conditional volatility.

We seem to observe different patterns of exchange at different times and in different places. The first goal of this paper is to develop a model of money as a medium of exchange which allows multiple transaction patterns. A dynamic version of Shubik’s trading post economy is used, and it is shown that this economy allows a role for fiat money, and that fiat money can coexist with barter in exchange. There are multiple decentralized equilibria, and one of these resembles the equilibrium of a cash-in-advance economy—indeed, the model can be viewed as a generalization of the cash-in-advance framework. The second goal of the paper is to show that the present model can help explain why inflation seems far more disruptive and costly than what is implied by empirical studies on the cash-in-advance model. The argument for this is based on misestimations due to the unobservability of the patterns of exchange, which are variable in this model.

This paper provides intertemporal general-equilibrium investigation of the welfare and employment consequences of Europe’s move to a unified market, using a multicountry, multisector applied model with imperfect competition, increasing returns-to-scale, and product differentiation at the firm level. The oligopolistic game between firms is assumed to be Nash in output. In the short-term, market imperfections (such as oligopolistic profits and wage rigidities) may exist. These imperfections vanish in the long run, characterized by stock-flow equilibrium consistent with steady-state growth. “Europe 1992” is interpreted as the elimination of the possibility for oligopolistic firms to price-discriminate between client countries within the European Community. Investigations are performed under alternative wage determination mechanisms (flexible wages v.s. wage indexation). We show, among other things, that the gains remain modest when dynamic effects are taken into account, and that all member countries are not sure to gain from European integration in the long run.