This paper investigates empirically the dynamics of investors' beliefs and Bayesian uncertainty about the state of the economy as state variables that describe the time-variation in investment opportunities. Using measures of uncertainty constructed from the state probabilities estimated from two-state regime-switching models of aggregate market return and of aggregate output, I find a negative relationship between the level of uncertainty and asset valuations. This relationship shows substantial cross-sectional variation across portfolios sorted on size, book-to-market, and past returns, especially conditional on the state of the economy. I show that a conditional model with investors' beliefs and an uncertainty risk factor is remarkably successful in explaining a large part of the cross-sectional variation in average portfolio returns. The uncertainty risk factor retains its incremental explanatory power when compared to other conditional models such as the conditional CAPM. The Author 2008. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: [email protected]., Oxford University Press.

Firms in industry clusters have market prices that are more efficient than firms outside clusters. To establish causality, we analyze exogenous firm relocations and find that firms that relocate into industry clusters have higher levels of industry information in their prices. We argue that geographical proximity allows for information spillovers, reducing marginal cost to information producers. Our evidence supports this view: Analysts are more likely to cover stocks inside industry clusters, and when institutional investors have a large position in one stock in the industry cluster, they are more likely to hold other stocks in the same industry cluster.

We examine the high volume return premium across 41 different countries and find it to be a phenomenon found in both developed and emerging markets. The premium is not caused by systematic differences in risk or liquidity. Using Merton's (1987) investor recognition hypothesis as a guide, we find the magnitude of the premium is generally associated with country and firm characteristics hypothesized to affect returns subsequent to a change in a stock's visibility. We also characterize the time-series properties of the premium and consider economic trading strategies.

Using the degree of accessibility of foreign investors to emerging stock markets, or investibility, as a proxy for the extent of foreign investments, we assess whether investibility has a significant influence on the diffusion of global market information across stocks in emerging markets. We show that greater investibility reduces price delay to global market information. We also find that returns of highly investible stocks lead those of noninvestible stocks because they incorporate global information more quickly. These results are consistent with the idea that financial liberalization in the form of greater investibility yields informationally more efficient stock prices in emerging markets.