Martin Bodenstein

Oil Shocks and External Adjustment

This paper investigates how oil price shocks affect the trade balance and terms of trade in a two country DSGE model. We show that the response of the external sector depends critically on the structure of financial market risk-sharing. Under incomplete markets, higher oil prices reduce the relative wealth of an oil-importing country, and induce its nonoil terms of trade to deteriorate, and its nonoil trade balance to improve. The magnitude of the nonoil terms of trade response hinges on structural parameters that affect the divergence in wealth effects across oil importers and exporters, including the elasticity of substitution between oil and other inputs in production, and the discount factor. By contrast, cross-country wealth differences effectively disappear under complete markets, with the implication that oil shocks have essentially no effect on the nonoil terms of trade or the nonoil trade balance.

The Effects of Foreign Shocks When Interest Rates Are at Zero

In a two-country DSGE model, the effects of foreign demand shocks on the home country are greatly amplified if the home economy is constrained by the zero lower bound for policy interest rates. This result applies even to countries that are relatively closed to trade such as the United States. Departing from many of the existing closed-economy models, the duration of the liquidity trap is determined endogenously. Adverse foreign shocks can extend the duration of the trap, implying more contractionary effects for the home country; conversely, large positive shocks can prompt an early exit, implying effects that are closer to those when the zero bound constraint is not binding.

Oil Shocks and the Zero Bound on Nominal Interest Rates

Beginning in 2009, in many advanced economies, policy rates reached their zero lower bound (ZLB). Almost at the same time, oil prices started rising again. We analyze how the ZLB affects the propagation of oil shocks. As these shocks move inflation and output in opposite directions, their effects on economic activity are cushioned when monetary policy is constrained. The burst of inflation from an oil price increase lowers real interest rates at the ZLB and stimulates the interest-sensitive component of GDP, offsetting the usual contractionary effects. In fact, if the increase in oil prices is gradual, the persistent rise in inflation can cause a GDP expansion.

International Asset Markets and Real Exchange Rate Volatility

The real exchange rate is very volatile relative to major macroeconomic aggregates and its correlation with the ratio of domestic over foreign consumption is negative (Backus-Smith puzzle). These two observations constitute a puzzle to standard international macroeconomic theory. This paper develops a two country model with complete asset markets and limited enforcement for international financial contracts that provides a possible explanation of these two puzzles. The model performs poorly with respect to asset pricing. However, with limited enforcement for both domestic and international financial contracts, the models asset pricing implications are brought into line with the empirical evidence, albeit at the expense of raising real exchange rate volatility.

Trade Elasticity of Substitution and Equilibrium Dynamics

The empirical literature provides a wide range of estimates for trade elasticities at the aggregate level. Furthermore, recent contributions in international macroeconomics suggest that low (implied) values of the trade elasticity of substitution may play an important role in understanding the disconnect between international prices and real variables. However, a standard model of the international business cycle displays multiple locally isolated equilibria if the trade elasticity of substitution is sufficiently low. The main contribution of this paper is to compute and characterize some dynamic properties of these equilibria. While multiple steady states clearly signal equilibrium multiplicity in the dynamic setup, this is not a necessary condition. Solutions based on log-linearization around a deterministic steady state are of limited to no help in computing the true dynamics. However, the log-linear solution can hint at the presence of multiple dynamic equilibria.

Closing Open Economy Models

Several methods have been proposed to obtain stationarity in open economy models. I find substantial qualitative and quantitative differences between these methods in a two-country framework, in contrast to the results of Schmitt-Grohe and Uribe (2003). In models with a debt elastic interest rate premium or a convex portfolio cost, both the steady state and the equilibrium dynamics are unique if the elasticity of substitution between the domestic and the foreign traded good is high. However, there are three steady states if the elasticity of substitution is sufficiently low. With endogenous discounting, there is always a unique and stable steady state irrespective of the magnitude of the elasticity of substitution. Similar to the model with convex portfolio costs or a debt elastic interest rate premium, though, there can be multiple convergence paths for low values of the elasticity in response to shocks.

Does the Time Inconsistency Problem Make Flexible Exchange Rates Look Worse than You Think

The Barro-Gordon inflation bias has provided the most influential argument for fixed exchange rate regimes. However, with low inflation rates now widespread, credibility concerns seem no longer relevant. Why give up independent monetary policy to contain an inflation bias that is already under control? We argue that credibility problems do not end with the inflation bias and they are a larger drawback for flexible exchange rates than usually thought. Absent commitment, independent monetary policy can induce expectation traps---that is, welfare ranked multiple equilibria---and perverse policy responses to real shocks, i.e., an equilibrium policy response that is welfare inferior to policy inaction. Both possibilities imply that flexible exchange rates feature unnecessary macroeconomic volatility.

Can the U.S. monetary policy fall (again) in an expectation trap

We provide a tractable model to study monetary policy under discretion. We restrict our analysis to Markov equilibria. We find that for all parametrizations with an equilibrium inflation rate of about 2 percent, there is a second equilibrium with an inflation rate just above 10 percent. Thus, the model can simultaneously account for the low and high inflation episodes in the United States. We carefully characterize the set of Markov equilibria along the parameter space and find our results to be robust, suggesting that expectation traps are more than just a theoretical curiosity.

Macroeconomic Policy Games

Strategic interactions between policymakers arise whenever each policymaker has distinct objectives. Deviating from full cooperation can result in large welfare losses. To facilitate the study of strategic interactions, we develop a toolbox that characterizes the welfare-maximizing cooperative Ramsey policies under full commitment and open-loop Nash games. Two examples for the use of our toolbox offer some novel results. The first example revisits the case of monetary policy coordination in a two-country model to confirm that our approach replicates well-known results in the literature and extends these results by highlighting their sensitivity to the choice of policy instrument. For the second example, a central bank and a macroprudential regulator are assigned distinct objectives in a model with financial frictions. Lack of coordination leads to large welfare losses even if technology shocks are the only source of fluctuations.

Of Nutters and Doves

We argue that there are conditions such that any inflation targeting regime is preferable to full policy discretion, even if long-run inflation rates are identical across regimes. The key observation is that strict inflation targeting outperforms the discretionary policy response to sufficiently persistent shocks. Under full policy discretion, inflation expectations over the medium term respond to the shock and thereby amplify its impact on output. As a result, little output stabilization is achieved at the cost of large and persistent inflation fluctuations.