Oxy adopted a shareholder rights plan.

The plan would provide stockholders with the right to buy certain preferred stock in the case of an unfriendly takeover. But that right could be exercised only if a person or group acquires 20% of Occidental Petroleum stock or if a tender offer is begun that would result in ownership of 30% or more of the company. The measures were not adopted in response to any effort to acquire the company, and Oxy officials said they don’t know of any such efforts.