HEALTH

Health Systems Adopts Shareholder Rights Plan: Health Systems International Inc., a Woodland Hills-based managed health-care firm, said it has adopted a so-called shareholder rights plan as a preventive measure against an unsolicited takeover. The plan would be triggered when a person or group acquires 15% or more of Health Systems’ stock, allowing company shareholders to buy stock at a discount of the market price. The company’s stock has dropped 20% in the last two months. This month, Health Systems pulled plans to sell 2.9 million shares because of a decline in its stock price. The stock decline began after Health Systems’ aborted merger attempt with rival WellPoint Health Networks Inc. and after the company began a reorganization.