[We theoretically and empirically investigate the role of information on the cross section of stock returns and firms' cost of capital when investors face estimation risk and learn from noisy signals of uncertain quality. The resultant equilibrium is an information-dependent conditional CAPM. We find strong empirical support for the model. Innovations in market volatility, oil prices, exchange rates, and dispersion of analysts' forecasts not only help explain the cross section of stock returns, but their influence depends on the stock's systematic estimation risk. Moreover, dividend and share repurchase initiations have significant downward announcement effects on estimated betas and their standard errors.]

We examine the long‐term stock performance following dividend initiations and resumptions from 1927 to 1998. We show that postannouncement abnormal returns are significantly positive for equally weighted calendar time portfolios, but become insignificant when the portfolios are value weighted. Moreover, the equally weighted results are not robust across subsamples. We also document postannouncement reductions in the risk factor loadings of underlying stocks. Cross‐sectionally, these reductions are negatively related to the contemporaneous price drifts, suggesting the price drifts may be a sample‐specific result of chance. Our results underscore the importance of testing for changes in risk loadings in future long‐term event studies.

Miller (1977) hypothesizes that dispersion of investor opinion in the presence of short-sale constraints leads to stock price overvaluation. However, previous empirical tests of Miller's hypothesis examine the valuation effects of only one of these two necessary conditions. We examine the valuation effects of the interaction between differences of opinion and shortsale constraints. We find robust evidence of significant overvaluation for stocks that are subject to both conditions simultaneously. Stocks are not systematically overvalued when either one of these two conditions is not met.

We theoretically and empirically investigate the role of information on the cross section of stock returns and firms' cost of capital when investors face estimation risk and learn from noisy signals of uncertain quality. The resultant equilibrium is an information-dependent conditional CAPM. We find strong empirical support for the model. Innovations in market volatility, oil prices, exchange rates, and dispersion of analysts' forecasts not only help explain the cross section of stock returns, but their influence depends on the stock's systematic estimation risk. Moreover, dividend and share repurchase initiations have significant downward announcement effects on estimated betas and their standard errors.