Research Database

Unit root tests against trend break alternatives are based on the premise that the dating of the trend breaks coincides with major economic events with permanent effects on economic activity, such as wars and depressions. Standard economic theory, however, suggests that these events have large transitory, rather than permanent, effects on economic activity. Conventional unit root tests against trend break alternatives based on linear ARIMA models do not capture these transitory effects and can result in severely distorted inference. We quantify the size distortions for a simple model in which the effects of wars and depressions can reasonably be interpreted as transitory. Monte Carlo simulations show that in moderate samples, the widely used Zivot-Andrews (1992) test mistakes transitory dynamics for trend breaks with high probability. We conclude that these tests should be used only if there are no plausible economic explanations for apparent trend breaks in the data.

I study asset prices in a two-agent macroeconomic model with two key features: limited stock market participation and heterogeneity in the elasticity of intertemporal substitution in consumption (EIS). The model is consistent with some prominent features of asset prices, such as a high equity premium; relatively smooth interest rates; procyclical stock prices; and countercyclical variation in the equity premium, its volatility, and in the Sharpe ratio. In this model, the risk-free asset market plays a central role by allowing non-stockholders (with low EIS) to smooth the fluctuations in their labor income. This process concentrates non-stockholders’ labor income risk among a small group of stockholders, who then demand a high premium for bearing the aggregate equity risk. Furthermore, this mechanism is consistent with the very small share of aggregate wealth held by non-stockholders in the US data, which has proved problematic for previous models with limited participation. I show that this large wealth inequality is also important for the model’s ability to generate a countercyclical equity premium. When it comes to business cycle performance the model’s progress has been more limited: consumption is still too volatile compared to the data, whereas investment is still too smooth. These are important areas for potential improvement in this framework.

We revisit the question of how capital should be taxed. We allow for a rich set of tax instruments that consists of taxes widely used in practice, including consumption, dividend, capital, and labor income taxes. We restrict policies to respect promises that the government has made in the previous period regarding the current value of wealth. We show that capital should not be taxed if households have preferences that are standard in the macroeconomics literature. We show that Ramsey outcomes that must respect such promises are time consistent. We show that the presumption in the literature that capital should be taxed for some length of time arises because the tax system is restricted.

We study financial panics in a small open economy with floating exchange rates. In our model, bank runs trigger a decline in domestic wealth and a currency depreciation. Runs are more likely when banks have dollar debt. Dollar debt emerges endogenously in response to the precautionary motive of domestic savers: dollar savings provide insurance against crises; so when crises are possible it becomes relatively more expensive for banks to borrow in local currency, which gives them an incentive to issue dollar debt. This feedback between aggregate risk and savers’ behavior can generate multiple equilibria, with the bad equilibrium characterized by financial dollarization and the possibility of bank runs. A domestic lender of last resort can eliminate the bad equilibrium, but interventions need to be fiscally credible. Holding foreign currency reserves hedges the fiscal position of the government and enhances its credibility, thus improving financial stability.

Using a simple model, we show why previous empirical studies of budget policy effects are flawed. Due to an identification problem, those studies’ findings can be shown to be consistent with either policies mattering or not.

This study examines the pricing of U.S. state banknotes before 1860 using discount data from New York, Philadelphia, Cincinnati, and Cleveland. The study determines whether these banknotes were priced consistent with their expected net redemption value as securities are. The evidence is mixed. Prices for a bank’s notes were higher when the bank was redeeming its notes for specie than when it was not, and banknote prices generally reflected the costs of note redemption. However, the relationship between prices and redemption costs was not tight, and there were cases in which the notes of distant banks went at par.

International trade is frequently thought of as a production technology in which the inputs are exports and the outputs are imports. Exports are transformed into imports at the rate of the price of exports relative to the price of imports: the reciprocal of the terms of trade. Cast this way, a change in the terms of trade acts as a productivity shock. Or does it? In this paper, we show that this line of reasoning cannot work in standard models. Starting with a simple model and then generalizing, we show that changes in the terms of trade have no first-order effect on productivity when output is measured as chain-weighted real GDP. The terms of trade do affect real income and consumption in a country, and we show how measures of real income change with the terms of trade at business cycle frequencies and during financial crises.

Measured aggregate U.S. consumption does not behave like a martingale. This paper develops and tests two variants of the permanent income model that are consistent with this fact. In both variants, we assume agents make decisions on a continuous time basis. According to the first variant, the martingale hypothesis holds in continuous time and serial persistence in measured consumption reflects only the effects of time aggregation. We investigate this variant using both structural and atheoretical econometric models. The evidence against these models is far from overwhelming. This suggests that the martingale hypothesis may yet be a useful way to conceptualize the relationship between aggregate quarterly U.S. consumption and income. According to the second variant of the permanent income model, serial persistence in measured consumption reflects the effects of exogenous technology shocks and time aggression. In this model, continuous time consumption does not behave like a martingale. We find little evidence against this variance of the permanent income model. It is difficult, on the basis of aggregate quarterly U.S. data, to convincingly distinguish between the different continuous time models considered in the paper.

A major motivation for the wave of privatizations of state-owned enterprises (SOEs) in the last twenty years was a belief that privatization would increase economic efficiency. There are now many studies showing most privatizations achieved this goal. Our theme is that the productivity gains from privatization are much more general and widespread than has typically been recognized in this literature. In assessing the productivity gains from privatization, the literature has only examined the productivity gains accruing at the privatized SOEs. But privatization may have significant impact on the private producers that often exist side-by-side with SOEs. In this paper we show that this was indeed the case when Brazil privatized its SOEs in the iron ore industry. That is, after their privatization, the iron ore SOEs dramatically increased their labor productivity, but so did the private iron ore companies in the industry.