The ex-dividend or distribution date is a crucial concept to understand in the world of finance. It refers to the date when a buyer of a stock is not entitled to the upcoming declared dividend or distribution. This is because the buyer will not be a holder of record. The ex-d date is typically two clearing days before the record date, which is set by the exchange where the stock is listed. It is important to be aware of this date when making investment decisions, as it can affect the overall return on investment.