Stock Returns on Ex-dividend Date: Advance disclosure and ordinary disclosure
Authors:   Asia-Europe Perspective Association, Khil Jaeuk , Han Sangjeon 
Published: April 2019

In this paper, we examine stock returns on ex-dividend date in the Korean market. Specifically, we divide the whole sample of firms which are listed on the KOSPI and KOSDAQ markets and have fiscal year ending in December into two distinguished sub-samples of advance disclosure and ordinary disclosure and compare their ex-dividend date stock price behaviors for the period from 2006 to 2016. An ex-dividend refers to the state of a stock where its shareholder does not have the right to receive dividends. An investor who purchases a stock before its ex-dividend date is entitled to receive the dividends, but if the stock is purchased on or after the ex-dividend date, the dividends will not be paid. Therefore, in an efficient market, it is reasonable to lower the ex-dividend price by dividends amount to be paid. In the Korean stock market, investment decisions on dividends accompany significant amount of uncertainties in most cases because investors are not aware of whether dividends will be paid or not and, if paid, what will be the dividend amounts before ex-dividend date. For this reason, it is difficult to make correct decisions for dividend investments, and stock prices on ex-dividend date are not likely to be formed efficiently. However, some firms make disclosures in advance about whether dividends are paid or not and dividend amount to be paid, which reduces significantly the uncertainty in dividend investments. For these firms with advance disclosure, investors can make dividend investments more efficiently based on the information disclosed, and as a result, it is highly likely that the information effect of dividends and the determination of share price in the market on ex-dividend date becomes more efficient. However, most studies for Korean firms have not considered these important differences and treated the whole sample firms as homogeneous without distinction between advance disclosure firms and ordinary disclosure firms. Based on the fact that about 95% of the cash dividends in Korean firms is ordinary disclosure, the analysis without considerations for advance disclosure firms would not reflect the characteristics of advance disclosure firms, and the results and implications derived from it would have some limitations. Considering these situations, this study conducts separate analyses for both advance disclosure firms and ordinary disclosure firms. Specifically, we examine whether there is a difference between the two groups for the degree to which the information conveyed by each disclosure type is reflected in the actual trades in the markets. Also, we examine how the stock returns on ex-dividend date depend on the dividend tax as well as the paid dividend amount in the empirical analyses. In order to examine whether the difference between the two groups are derived from the different characteristics of the exchanges where the firms are listed, we divide the whole sample firms into two sub-groups according to their exchanges and repeat same analysis separately. The results of the empirical analysis are as follows. First, there is a significant difference between the two groups in the abnormal returns. Second, paid dividend amounts are more accurately reflected in stock returns on ex-dividend date for advance disclosure firms than ordinary disclosure firms. These results are also observed in the sub-sample analysis across exchanges where the firms are listed. Our empirical results suggest that advance disclosure for dividends significantly reduces the uncertainty and therefore increases the efficiency of stock price behaviors on ex-dividend date. Therefore, policies which provide incentives increasing the use of advance disclosure for dividends before ex-dividend date, would improve the efficiency of the market as a whole.