Dallas-based Tenet Healthcare Corporation has issued a so-called "poison pill" clause to stave off a potential takeover by rival hospital operator Community Health Systems. In this instance, Tenet's board has made it far easier for existing shareholders to buy up stock in the company should a new shareholder suddenly acquire a large block of shares. Tenet also pushed back its annual meeting to November--several months later than is typical. Tenet recently rejected a buyout offer by Tennessee-based Community, which issued a statement urging the company to negotiate in good faith. --Read the full article at FierceHealthcare