Final answer:
The date on which a stockholder must purchase stock before to receive a dividend is called the ex-dividend date.
Step-by-step explanation:
The date on which a stockholder must purchase stock in order to receive a dividend is called the ex-dividend date.
On this date, the stock starts trading without the right to receive the upcoming dividend. If an investor purchases the stock on or after the ex-dividend date, they will not be eligible to receive the dividend payment.