The correlation between uncertainty shocks, as measured by changes in the VIX, and changes in break-even inflation rates declined and turned negative after the Great Recession. This estimated time-varying correlation is shown to be consistent with the predictions of a standard New Keynesian model with a lower bound on interest rates and a trend decline in the natural rate of interest. In one equilibrium of the model, higher uncertainty raises the probability of large shocks that leave the central bank constrained by the lower bound and unable to offset negative shocks. Resulting inflation shortfalls lower average inflation rates.

This paper analyzes the effects of the lower bound for interest rates on the distributions of inflation and interest rates. In a New Keynesian model with a lower bound, two equilibria emerge: policy is mostly unconstrained in the “target equilibrium,” whereas policy is mostly constrained in the “liquidity trap equilibrium.” Using options data on interest rates and inflation, we find forecast densities consistent with the target equilibrium and find no evidence in favor of the liquidity trap equilibrium. The lower bound has a sizable effect on the distribution of interest rates, but its impact on inflation is relatively modest.

We show that the stock market may fail to aggregate information even if it appears to be efficient, and that the resulting decrease in the information content of prices may drastically reduce welfare. We solve a macroeconomic model in which information about fundamentals is dispersed and households make small, correlated errors when forming expectations about future productivity. As information aggregates in the market, these errors amplify and crowd out the information content of stock prices. When prices reflect less information, the conditional variance of stock returns rises, causing an increase in uncertainty and costly distortions in consumption, capital accumulation, and labor supply.

We present a model in which investors decide whether or to what degree they want to allow their behavior to be influenced by “market sentiment.” Investors who choose to insulate their decisions from market sentiment earn higher expected returns, but incur a small mental cost. We show that if information is moderately dispersed across investors, even a very small mental cost may result in a significant amount of sentiment in equilibrium: Individuals who choose to be swayed by sentiment increase uncertainty about the future and make it less costly for others to be swayed by sentiment as well.

We develop a novel, risk-based theory of the effects of exchange rate stabilization. In our model, the choice of exchange rate regime allows policymakers to make their currency, and by extension, the firms in their country, a safer investment for international investors. Policies that induce a country’s currency to appreciate when the marginal utility of international investors is high lower the required rate of return on the country’s currency and increase the world-market value of domestic firms. Applying this logic to exchange rate stabilizations, we find a small economy stabilizing its bilateral exchange rate relative to a larger economy can increase domestic capital accumulation, domestic wages, and even its share in world wealth. In the absence of policy coordination, small countries optimally choose to stabilize their exchange rates relative to the currency of the largest economy in the world, which endogenously emerges as the world’s “anchor currency”, Larger economies instead optimally choose to float their exchange rates. The model therefore predicts an equilibrium pattern of exchange rate arrangements that is remarkably similar to the one in the data.