Net Foreign Assets and the Exchange Rate: Redux Revived

We revisit Obstfeld and Rogoff's (1995) results on exchange rate dynamics in a two-country, monetary model with incomplete asset markets, stationary net foreign assets, and endogenous nominal interest rate setting a la Taylor (1993). Under flexible prices, the nominal exchange rate exhibits a unit root. However, today's exchange rate also depends on the stock of real net foreign assets accumulated in the previous period. The predictive power of net assets for the exchange rate is stronger the closer assets to non-stationary and the higher the degree of substitutability between domestic and foreign goods in consumption. When prices are sticky, the exchange rate still exhibits a unit root. The current level of the exchange rate depends on the past GDP differential, along with net foreign assets. Endogenous monetary policy and asset dynamics have consequences for exchange rate overshooting under both flexible and sticky prices.exchange rate, monetary policy, net foreign assets, overshooting

International Trade and Macroeconomic Dynamics with Heterogeneous Firms

We develop a stochastic, general equilibrium, two-country model of trade and macroeconomic dynamics. Productivity differs across individual, monopolistically competitive firms in each country. Firms face some initial uncertainty concerning their future productivity when making an irreversible investment to enter the domestic market. In addition to the sunk entry cost, firms face both fixed and per-unit export costs. Only a subset of relatively more productive firms export, while the remaining, less productive firms only serve their domestic market. This microeconomic structure endogenously determines the extent of the traded sector and the composition of consumption baskets in both countries. Exogenous shocks to aggregate productivity, sunk entry costs, and trade costs induce firms to enter and exit both their domestic and export markets, thus altering the composition of consumption baskets across countries over time. The microeconomic features have important consequences for macroeconomic variables. Macroeconomic dynamics, in turn, feed back into firm level decisions, further altering the pattern of trade over time. Our model generates deviations from purchasing power parity that would not exist absent our microeconomic structure with heterogeneous firms. It provides an endogenous, microfounded explanation for a Harrod-Balassa-Samuelson effect in response to aggregate productivity differentials and deregulation. In addition, the deviations from purchasing power parity triggered by aggregate shocks display substantial endogenous persistence for very plausible parameter values, even when prices are fully flexible.Heterogeneous firms, Endogenous non-tradedness, Real exchange rate, Persistence, Harrod-Balassa-Samuelson effect

International Trade and Macroeconomic Dynamics with Heterogeneous Firms

We develop a stochastic, general equilibrium, two-country model of trade and macroeconomic dynamics. Productivity differs across individual, monopolistically competitive firms in each country. Firms face a sunk entry cost in the domestic market and both fixed and per-unit export costs. Only relatively more productive firms export. Exogenous shocks to aggregate productivity and entry or trade costs induce firms to enter and exit both their domestic and export markets, thus altering the composition of consumption baskets across countries over time. In a world of flexible prices, our model generates endogenously persistent deviations from PPP that would not exist absent our microeconomic structure with heterogeneous firms. It provides an endogenous, microfounded explanation for a Harrod-Balassa-Samuelson effect in response to aggregate productivity differentials and deregulation. Finally, the model successfully matches several moments of U.S. and international business cycles.

The Valuation Channel of External Adjustment

This paper explores the valuation channel of external adjustment in a two-country dynamic stochastic general equilibrium model (DSGE) with international equity trading. The theoretical model we set up matches key moments of the data for the United States at business cycle frequency at least as well as standard models of international real business cycles (RBCs). In our theoretical analysis, we find that two-asset trading is necessary for a valuation channel of external adjustment to emerge. However, other features of the economy, such as on the nature of the shock that generates the external imbalance and other features of the economy – the extent of nominal rigidity and the size of finacial frictions – determine the magnitude and significance of this channel of adjustment. The relative importance of the valuation channel is larger the higher the degree of nominal rigidity and the higher finacial intermediation costs. Monetary policy shocks have no valuation effects with flexible prices and trade only in equity. Specifying the theoretical model with net foreign assets different from zero in necessary to start matching satisfactorily empirical moments of changes in the US net foreign asset position.External adjustment, Portfolio Models, Valuation Channel, SDGE Models

The Valuation Channel of External Adjustment

Ongoing international financial integration has greatly increased foreign asset holdings across countries, enhancing the scope for a "valuation channel" of external adjustment (i.e., the changes in a country's net foreign asset position due to exchange rate and asset price changes). We examine this channel of adjustment in a dynamic stochastic general equilibrium model with international equity trading in incomplete asset markets. We show that the risk-sharing properties of international equity trading are tied to the distribution of income between labor income and profits when equities are defined as claims to firm profits in a production economy. For a given level of international financial integration (measured by the size of gross foreign asset positions), the quantitative importance of the valuation channel of external adjustment depends on features of the international transmission mechanism such as the size of financial frictions, substitutability across goods, and the persistence of shocks. Finally, moving from less to more international financial integration, risk sharing through asset markets increases, and valuation changes are larger, but their relative importance in net foreign asset dynamics is smaller.

Trade Flow Dynamics with Heterogeneous Firms

We use a two-country, stochastic, general equilibrium model of international trade and macroeconomic dynamics with monopolistic competition and heterogeneous firms to explore the role of entry in the domestic economy and the extensive margin of international trade in the dynamics of U.S. trade flows over the business cycle. We show that the model can reproduce the evidence on the cyclicality of U.S. trade and important features of the evidence on the extensive margins of domestic entry and international trade. Entry in the domestic economy and the implied differences in the timing of export and import expansions in response to favorable productivity shocks provide the key mechanism for the model's ability to explain this range of stylized facts.Economic

Endogenous Entry, Product Variety, and Business Cycles

This paper builds a framework for the analysis of macroeconomic fluctuations that incorporates the endogenous determination of the number of producers over the business cycle. Economic expansions induce higher entry rates by prospective entrants subject to irreversible investment costs. The sluggish response of the number of producers (due to the sunk entry costs) generates a new and potentially important endogenous propagation mechanism for real business cycle models. The stock-market price of investment (corresponding to the creation of new productive units) determines household saving decisions, producer entry, and the allocation of labor across sectors. The model performs at least as well as the benchmark real business cycle model with respect to the implied second-moment properties of key macroeconomic aggregates. In addition, our framework jointly predicts a procyclical number of producers and procyclical profits even for preference specifications that imply countercyclical markups. When we include physical capital, the model can reproduce the variance and autocorrelation of GDP found in the data.

Optimal Monetary Policy with Endogenous Entry and Product Variety

We show that deviations from long-run stability of product prices are optimal in the presence of endogenous producer entry and product variety in a sticky-price model with monopolistic competition in which price stability would be optimal in the absence of entry. Specifically, a long-run positive (negative) rate of inflation is optimal when the benefit of variety to consumers falls short of (exceeds) the market incentives for creating that variety under flexible prices, governed by the desired markup. Plausible preference specifications and parameter values justify a long-run inflation rate of two percent or higher. Price indexation implies even larger deviations from long-run price stability. However, price stability (around this non-zero trend) is close to optimal in the short run, even in the presence of time-varying flexible-price markups that distort the allocation of resources across time and states. The central bank uses its leverage over real activity in the long run, but not in the short run. Our results point to the need for continued empirical research on the determinants of markups and investigation of the benefit of product variety to consumers.