The date on which any right on a stock that has been declared, but not distributed, belongs legally to its seller rather than the buyer. That is, when one sells a stock on or after the ex-rights date, the right will remain with the seller when it is distributed. On the other hand, if it is sold before the ex-rights date, the right will go to the buyer. See also: Ex-dividend date.
The first day of trading on which new buyers of a firm's stock will not be entitled to receive recently declared rights to buy shares in a new security issue.