The most important characteristic of the most effective rights plan (position pill) in use today. It gives shareholders the right to buy the company’s shares at half price when someone becomes an ‘interested shareholder’, that is, crosses some stock ownership threshold such as 15% or 20%. The interested shareholder’s rights are void. Other shareholders can (typically) use each of their rights to buy a number of shares equal to two times the exercise price (set in advance), divided by the current market price of the target company’s stock. Usually, from the standpoint of a bidder, the flip-in right is a complete show stopper unless the bidder can convince a court that it should intervene. In the text we have tried to describe when courts intervene against poison pills under Delaware law.