Twitter's board has adopted a 'poison pill' plan to prevent a hostile takeover by Elon Musk, who has offered to buy the company for $43 billion. The plan allows existing shareholders to purchase additional shares at a discount if any entity acquires 15% or more of Twitter's outstanding common stock without the board's approval. Musk already owns over 9% of Twitter's shares and has expressed his desire to make the company's algorithms more publicly accessible and limit content moderation. The move is seen as a common way to fend off a potential hostile takeover.