In 1970, E. Elton and M. Gruber suggested that the price drop on ex-dividend days may be used as an estimator of the tax rate on dividends for the marginal investor. Their statistic is still being used to assess clientele effects for dividends and financial structures as well as the consequences...

The ratio of price changes to dividends is sometimes used to assess personal tax rates and detect tax clientele for dividends. It is suggested here that the model is unable to detect possible tax effects, given the sample sizes available to most researchers.