Due to the overwhelming international evidence that stock prices drop by less than the dividend paid on ex-dividend days, the ex-dividend day anomaly is considered a stylized fact. Two main approaches have emerged to explain this empirical regularity: the tax-clientele hypothesis and the microstructure of financial markets. Although the most widely accepted explanation for this fact relies on taxes, the ex-dividend day anomaly has been reported even in countries where
IntroductionUnder perfect capital markets, the price of a share should drop by exactly the dividend per share paid on ex-dividend days. Nevertheless, researchers consistently report that prices fall by less than the dividend per share paid. The results are similar across countries and do not depend on the period investigated. This behavior constitutes an empirical regularity of stock returns that has been defined as the ex-dividend day anomaly. In a pioneer investigation with a small sample of companies quoted in the New York Stock Exchange, Campbell and Beranek (1955) reported that stock prices adjusted by less than the dividend paid. They observed that prices dropped on average by 90% of the dividend paid on ex-dividend dates. The authors, however, did not offer any explanation for this anomalous behavior. Later, Elton and Gruber (1970) proposed a tax-clientele explanation for their similar finding that stock prices dropped on average by 77.7% of the dividend paid. The authors suggested that, since dividends were usually taxed at higher rates than capital gains, the drop of the stock price should be smaller than the dividend paid to make investors indifferent between selling the stock cum-dividend and holding the stock, obtaining the dividend, and selling the stock ex-dividend. The greater the difference between dividends and capital gains tax rates, the smaller the price drop should be. In addition, the authors found that as the stock dividend yield increased, so did the price adjustment expressed as a percentage of the dividend per share. Such behavior supported their proposed tax-* The authors would like to thank two anonymous referees for their comments and suggestions.Finance a úvěr-Czech Journal of Economics and Finance, 61, 2011, no. 2 141 -clientele hypothesis: since those investors with relatively high tax rates would prefer to invest in low dividend yield stocks, these stocks should show a stronger tax effect than high yield ones, and therefore smaller price adjustments.Following Elton and Gruber (1970), many papers have carried out similar investigations in stock markets worldwide, most of them supporting the tax-clientele hypothesis for the reported less than one hundred percent price adjustment. Among these papers, we can mention Poterba and Summers (1984), Robin (1991), Graham et al. (2003), Zang et al. (2008), Amromim et al. (2008), and, more recently, Witworth and Rao (2010) for the United States; Athanassakos (1996) for Canada; Hayashi and Jagannathan (1990) for Japan; Poterba and Summers (1985) for the United Kingdom; a...