No abstract

No abstract

We investigate the dynamic problem of how much attention an investor should pay to news in order to learn about stock-return predictability and maximize expected lifetime utility. We show that the optimal amount of attention is U-shaped in the return predictor, increasing with both uncertainty and the magnitude of the predictive coefficient and decreasing with stock-return volatility. The optimal risky asset position exhibits a negative hedging demand that is hump shaped in the return predictor. Its magnitude is larger when uncertainty increases but smaller when stock-return volatility increases. We test and find empirical support for these theoretical predictions. This paper was accepted by Gustavo Manso, finance.

We propose a rational model to explain time-series momentum. The key ingredient is word-of-mouth communication, which we introduce in a noisy rational expectations framework. Word-of-mouth communication accelerates information revelation through prices and generates short-term momentum and long-term reversal. Social interactions allow investors with heterogeneous trading strategies-contrarian and momentum traders-to coexist in the marketplace. As a result, momentum is not completely eliminated, although a significant proportion of investors trade on it. We also show that word-of-mouth communication spreads rumors and generates price run-ups and reversals. Our theoretical predictions are in line with several empirical findings.