Cum dividend refers to a stock price, which means ‘with dividend’ or a stock price which includes the amount of dividend, which has been declared, but not paid yet. A stock is ‘cum dividend’ and will trade so, until the ex-dividend date. After the ex-dividend date, it trades without its dividend rights or dividend price and is known as ‘ex-dividend’. An investor who sells a share before its ‘ex-dividend’ date is selling the stock ‘cum dividend’ which means with dividend or without waiting to realise the benefit of receiving the dividend amount already declared by the company. This is more a factor of timing of the sell trade.