Research

This paper studies determinacy conditions in a monetary model with an interest rate rule. In addition to the inflation rate as an argument of the policy rule, we introduce a second argument: output, a case empirically relevant but overlooked in the existing literature on monetary models with flexible prices. Firstly, we estimate a model with money in utility and the production function. We find that an aggressive response to inflation does not necessarily guarantee determinacy anymore. Secondly, we compare monetary policy in the pre-Volcker era and the post-Volcker era. We find that, after the appointment of Paul Volcker, the Federal Reserve started to respond more aggressively to inflation and less aggressively to output. Indeterminacy is pervasive: the equilibrium is indeterminate in both sub-samples. Thirdly, we estimate the impulse response functions. We find that monetary shocks, sunspot inflation shocks, and productivity shocks have long-lasting effects on inflation, output, and interest rates.

Financial crises tend to spread across countries, causing equity price crashes that cannot be fully explained by fundamentals. This paper introduces a two-country dynamic general equilibrium model of global financial crises that distinguishes between interdependence and financial contagion. Interdependence arises through trade and capital flows, while contagion occurs through a new channel: confidence spillovers. In the model, contagion is possible due to multiple dynamic and steady-state equilibria, even with fully rational consumers. Self-fulfilling beliefs about equity prices can shift the economy between equilibria, amplifying negative effects and causing contagion. The model has three policy implications. Firstly, monetary policy can offset recessions without causing inflation. Coordinated international policy can potentially improve welfare further.  Secondly, capital controls can prevent contagion. Lastly, increased trust in government can mitigate negative confidence shocks. These recommendations emphasize the role of beliefs, where pessimism can spread internationally via the confidence channel, leading to contagion.

Central banks set the nominal interest rate to target inflation and stabilize output. In monetary models, monetary policy affects output directly via the wealth effect. I show that in these models, the response of the central bank to fluctuations in output may induce real indeterminacy even if the Taylor principle is satisfied. I find that the determinacy conditions depend on the interest elasticity of output and generally, the Taylor principle is neither necessary nor sufficient for determinacy. This is in stark contrast with the New Keynesian model where a sufficiently strong policy response to inflation or output usually ensures determinacy.

We integrate Keynesian economics with general equilibrium theory in a new way. We develop a simple graphical apparatus, the IS-LM-NAC framework, that can be used by policy makers to understand how policy affects the economy. A new element, the No-Arbitrage-Condition (NAC) curve, connects the interest rate to current and expected future values of the stock market and it explains how ‘animal spirits’ influence economic activity. Our framework provides a rich new approach to policy analysis that explains the short-run and long-run effects of policy.

Following the COVID-19 pandemic, U.S. output rebounded quickly, labor productivity rose above pre-pandemic levels, profit rates increased, and the labor market tightened, all despite high unemployment. These observations can be reconciled in a search and matching model of the labor market with two key assumptions: firm market power and endogenous labor demand. Market power encourages firm entry when prices rise, while endogenous labor demand allows firms to adapt to shocks rather than shut down. Two regimes arise: with weak market power, representing the pre-pandemic era, and with strong market power, explaining the post-pandemic recovery. Under strong market power, firm entry drives a quick recovery after recessions: the labor market tightens, wages and producer prices go up, and the average firm size shrinks, consistent with the post-pandemic data. This paper shows how a typical business cycle can be reconciled with the post-pandemic recovery in a unified model.