poison pill poison pill A tactic in which a company discourages unwanted takeover bids by ensuring that a successful bid will trigger some event that substantially reduces the value of the company. Examples of such tactics include the sale of some prized asset to a friendly company or bank or the issue of securities with a conversion option enabling the bidder’s shares to be bought at a reduced price if the bid is successful. See alsoporcupine provisions; staggered directorships. |