We consider optimal monetary stabilization policy in a New Keynesian model with explicit microfoundations, when the central bank recognizes that private-sector expectations need not be precisely model-consistent, and wishes to choose a policy that will be as good as possible in the case of any...

We study a standard consumption based asset pricing model with rational investors who entertain subjective prior beliefs about price behavior. Optimal behavior then dictates that investors learn about price behavior from past price observations. We show that this imparts momentum and mean...

When is it optimal for a government to default on its legal repayment oblig- ations? We answer this question for a small open economy with domestic production risk in which the government optimally finances itself by issuing non-contingent debt. We show that Ramsey optimal policies occasionally...

The booms and busts in U.S. stock prices over the post-war period can to a large extent be explained by fluctuations in investors' subjective capital gains expectations. Survey measures of these expectations display excessive optimism at market peaks and excessive pessimism at market throughs....

We present a stock market model that quantitatively replicates the joint behavior of stock prices, trading volume and investor expectations. Stock prices in the model occasionally display belief-driven boom and bust cycles that delink asset prices from fundamentals and redistribute considerable...