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.

Sovereign debt crises are associated with large and persistent declines in economic activity, disproportionately so for nontradable sectors. This paper documents this pattern using Spanish data and builds a two-sector dynamic quantitative model of sovereign default with capital accumulation. Recessions are very persistent in the model and more pronounced for nontraded sectors because of default risk. An adverse domestic shock increases the likelihood of default, limits capital inflows, and thus restricts the ability of the economy to exploit investment opportunities. The economy responds by reducing investment and reallocating capital toward the traded sector to support debt service payments. The real exchange rate depreciates, a reflection of the scarcity of traded goods. We find that these mechanisms are quantitatively important for rationalizing the experience of Spain during the recent debt crisis.

We construct a competitive model of innovation and growth under constant returns to scale. Previous models of growth under constant returns cannot model technological innovation. Current models of endogenous innovation rely on the interplay between increasing returns and monopolistic markets. In fact, established wisdom claims monopoly power to be instrumental for innovation and sees the nonrivalrous nature of ideas as a natural conduit to increasing returns. The results here challenge the positive description of previous models and the normative conclusion that monopoly through copyright and patent is socially beneficial.

This paper develops a theory of pricing-to-market driven by marketing and bargaining frictions. Our key innovation is a capital theoretic model of marketing in which relations with customers are valuable. In our model, producers search and form long-lasting relations with their customers, and marketing helps overcome the search frictions involved in forming such matches. In the context of international business cycle patterns, the model accounts for observations that are puzzles for a large class of theories: (i) pricing-to-market, (ii) positive correlation of aggregate real export and import prices, (iii) excess volatility of the real exchange rate over the terms of trade, and (iv) low short-run and high long-run price elasticity of international trade flows. The behavior of quantities is shown to be on par with standard international business cycle theories that, in contrast to our model, assume low intrinsic elasticity of substitution between domestic and foreign goods.

Total factor productivity (TFP) differs greatly across countries. In this paper, I provide a novel rationalization for these differences. I consider two environments, one in which enforcement is full and the other in which enforcement is limited. In both settings, manufactured goods can be produced using a high-TFP technology or a low-TFP technology; there is a fixed cost associated with adoption of the former. I suppose that the fixed cost is sufficiently small that adoption takes place in a symmetric Pareto optimum in the limited-enforcement setting. Under this condition, I prove two results. First, adoption takes place in all Pareto optima in the full-enforcement setting. Second, adoption may not take place in a Pareto optimum in the limited-enforcement setting, if the division of social surplus is sufficiently unequal. I conclude that limited enforcement and high inequality interact to create particularly strong barriers to riches (in the language of Parente and Prescott (1999, 2000).

This study argues that both unequal opportunity and social mobility are necessary implications of an efficient societal arrangement when incentives must be provided.

This paper presents a frequency-domain technique for estimating distributed lag coefficients (the impulse-response function) when observations are randomly missed. The technique treats stationary processes with randomly missed observations as amplitude-modulated processes and estimates the transfer function accordingly. Estimates of the lag coefficients are obtained by taking the inverse transform of the estimated transfer function. Results with artificially created data show that the technique performs well even when the probability of an observation being missed is one-half and in some cases when the probability is as low as one-fifth. The approximate asymptotic variance of the estimator is also calculated in the paper.

We present a general equilibrium model of the response of firms' decisions to operate, innovate, and engage in international trade to a change in the marginal cost of international trade. We find that, although a change in trade costs can have a substantial impact on heterogeneous firms' exit, export, and process innovation decisions, the impact of changes in these decisions on welfare is largely offset by the response of product innovation. Our results suggest that microeconomic evidence on firms' responses to changes in international trade costs may not be informative about the implications of changes in these trade costs for aggregate welfare.

The paper studies a fiscal policy instrument that can reduce fiscal distortions without affecting revenues, in a politically viable way. The instrument is a private contract (tax buyout), offered by the government to each citizen, whereby the citizen can choose to pay a fixed price in exchange for a given reduction in her tax rate for a period of time. We introduce the tax buyout in a dynamic overlapping generations economy, calibrated to match several features of the US income, taxes and wealth distribution. Under simple pricing, the introduction of the buyout is revenue neutral but, by reducing distortions, it benefits a significant fraction of the population and leads to sizable increases in aggregate labor supply, income and consumption.