The shareholder's rights plan is a formal name for the poison pill strategy we quoted earlier. If musk starts buying twitter shares and his ownership breaches the 15 % mark, then the company will issue more shares to existing investors at a discount. This way, they will keep diluting his ownership every time he makes progress. In 20 netflicks used a poison pill strategy to prevent the activist in wester karlai khan from acquiring the company. So yes, it is a tried and tested strategy. And while it may invite short term disruptions, it has been incredibly effective in preventing hostile takeovers.