Cum Rights is a term used to describe a stock that is the subject of a rights offering and is trading with the rights attached to the common stock.
Applying "Cum Rights" to Securities Exams:
When a corporation declares a rights offering each share of stock will receive a right. When the stock is trading in the market place with the rights attached new purchasers of the stock will receive the right when they purchase the shares in the market place. The stock is said to be trading cum rights.