The most famous anti-takeover device. It normally takes the form of granting existing stockholders (other than stockholders who acquire more than a certain percentage of the company) the option (which can only be exercised upon certain events) to buy more stock on very favourable terms as a way of diluting the position of the person trying to take control. See 'Anti-Takeover Provisions', 'Blank Cheque Preferred Stock', 'Shark Repellent,' and 'Staggered Board of Directors'.