'Epidemiological' models of belief formation put social interactions at their core; such models are widely used by scholars who are not economists to study the dynamics of beliefs in populations. We survey the literature in which economists attempting to model the consequences of beliefs about...

We introduce "smooth diagnosticity." Under smooth diagnosticity, agents over-react to new information defined as the difference between the current information set and a previous information set. Since new information typically changes not just the conditional mean, but also the conditional...

With fixed costs of participating in the stock market, consumers with high income will participate in the stock market, but consumers with lower income will not participate. If a fully-funded defined-contribution social security system tries to exploit the equity premium by selling a dollar of...

A growing body of new research has emphasized the macroeconomic consequences of transactional impediments in factor markets, and their role in the recurrent restructuring requirements of modern economies. We first review the function institutional arrangements play in facilitating transactions...

This paper examines stock market co-movements. It begins with a discussion of several conceptual issues involved in measuring these movements and how to test for contagion. Standard tests examine if cross-market correlation in stock market returns increase during a period of crisis. The measure...

If firms purchase capital up to the point where there is no further marginal benefit, and the firms' securities are equal in value to the capital, then the market value of securities measures the quantity of capital. I explore the implications of this hypothesis using data from U.S. non-farm,...

In this paper, we test the random walk hypothesis for weekly stock market returns by comparing variance estimators derived from data sampled at different frequencies. The random walk model is strongly rejected for the entire sample period (1962-1985) and for all sub-periods for a variety of...

The most familiar interpretation for the large and unpredictable swings that characterize common stock price indices is that price changes represent the efficient discounting of "new information" It is remarkable given the popularity of this interpretation that it has never been established what...