This is decided by the board of directors. Equity registration date: The board of directors will meet quarterly (or at regular intervals) to discuss how much of the company's profits (in some cases) will be "distributed" to shareholders in the form of "cash dividends". If dividends are declared, the directors will also set a "registration date", which means that shareholders registered before this date are entitled to dividends. Generally, the stock price will fall on the "trading day" after registration, which is equivalent to the amount of dividends. In other words, the stock will be ex-dividend after that date. Of course, the day of buying and selling stocks is naturally a trading day, and the fund open day is the day when investors are allowed to subscribe and redeem the same fund.