AMERON <AMN> ADOPTS SHAREHOLDER RIGHTS PLAN Ameron Inc said its board adopted a rights plan designed to protect shareholders from potentially unfair takeover tactics. The plan calls for distribution of one right for each of its outstanding common shares and each right entitles the holder to buy one/one-hundredth of a share of newly authorized Series A Junior Participating cumulative Preferred stock at an exercise price of 55 dlrs, Ameron said. It said the rights are exercisable if a group acquires 20 pct or more of its common stock or announces a tender offer for 30 pct or more of its shares.