Ex-dividend day price and volume: the case of cum-ex trading

In this paper, we analyse the extent of cum-ex trading in European markets. We document that the abnormal trading activity around the dividend day of a stock can be attributed to cum-ex trading, in addition to existing tax clientele hypotheses. Cum-ex trading is positively associated with dividend yield, which is consistent with maximizing returns from this strategy. Based on abnormal trading volume, we estimate a substantial loss to treasuries due to illicit tax refunds of withholding tax on dividends. Our results are robust, controlling for confounding effects and investors' tax preference and heterogeneity.