[We provide a comprehensive empirical analysis of stock price behavior around the ex-dividend day in Japan. We find that prices rise on the ex-day and that dividend-related tax effects appear to be secondary. Returns around ex-dividend days are dominated by the proximity of many ex-days to the fiscal year end. Excess returns of 1 percent, which are independent of any dividend-related considerations, are higher than round-trip transaction costs on medium-sized transactions. Prices seem to imply selling pressure before and buying pressure at the start of the new fiscal year. These trading patterns appear to be motivated by intercorporate manipulative trading around the end of the firms' fiscal year, which are unrelated to dividends.]

We provide a comprehensive empirical analysis of stock price behavior around the ex-dividend day in Japan. We find that prices rise on the ex-day and that dividend-related tax effects appear to be secondary. Returns around ex-dividend days are dominated by the proximity of many ex-days to the fiscal year end. Excess returns of 1 percent, which are independent of any dividend-related considerations, are higher than round-trip transaction costs on medium-sized transactions. Prices seem to imply selling pressure before and buying pressure at the start of the new fiscal year. These trading patterns appear to be motivated by intercorporate manipulative trading around the end of the firms’ fiscal year, which are unrelated to dividends.

Prior theoretical work on estimation risk generally has been restricted to single-period, returns-based models in which the investor must estimate the vector of expected returns but the covariance matrix is known. This paper extends the literature on parameter uncertainty in several ways. First, we analyze asymmetric parameter uncertainty in a model based on payoffs. Second, we explore the effects of both symmetric and asymmetric estimation risk on equilibrium asset prices when the covariance matrix for payoffs must also be estimated. Finally, we investigate the effects on equilibrium of asymmetric parameter uncertainty in a simple multiperiod model.