I have no idea what a shareholders rights plan was but after looking around on the web it has some pros and cons. I found this definition on the web and I think it gives us cuu longs some awesome rights!

Shareholder rights plans

The target company issues rights to existing shareholders to acquire a large number of new securities, usually common stock or preferred stock. The new rights typically allow holders (other than a bidder) to convert the right into a large number of common shares if anyone acquires more than a set amount of the target's stock (typically 15%). They dilute the percentage of the target owned by the bidder, and make it more expensive to acquire control of the target. This form of poison pill is sometimes called a shareholder rights plan because it provides shareholders (other than the bidder) with rights to buy more stock in the event of a control acquisition.[6]

The goal of a shareholder rights plan is to force a bidder to negotiate with the target's board and not directly with the shareholders. The effects are twofold:[7]

• It gives management time to find competing offers that maximizes selling price.
• Several studies indicate that companies with poison pills (shareholder rights plans) have received higher takeover premiums than companies without poison pills. This results in increased shareholder value. The theory is that an increase in the negotiating power of the target is reflected in higher acquisition premiums.