Ex rights is the term used to describe the common stock subject to a rights offering trade without the rights attached.
Applying "Ex Rights" to Securities Exams:
If a corporation wants to issue more shares pursuant to a rights offering each outstanding common share will receive the rights. During the term when the stock trades with the rights attached the stock is said to be trading cum rights. When the rights expire or become freely tradable the stock is said to be trading ex rights or without the rights attached.