Last Friday, corporate raider Carl Icahn asked Clorox (NYSE: CLX) if it wanted to get together for a cozy $76.50 per share, nearly a 12% premium to the previous day's close. This came shortly after Icahn quietly amassed 10 million shares last quarter. Clorox responded that it wanted to take it slow, sleep on it, and get back to him.

On Monday, Clorox announced that its board had unanimously rejected Icahn's unsolicited bid to acquire the company. The board believes the bid substantially undervalues Clorox and that the company's own strategic plan is in the best interests of shareholders.

The deal itself had drawn some skepticism after Icahn suggested that competitors such as Procter & Gamble (NYSE: PG), Colgate-Palmolive (NYSE: CL), or Kimberly-Clark (NYSE: KMB) would gladly pay up to $100 per share. Apparently, even the market didn't really believe Icahn was too serious, since the stock closed at $74.55 on the day the offer was made, nearly $2 below Icahn's offer price. Either way you look at it, his move has boosted Clorox shares to a 52-week high of $75.44, so you won't find any shareholders complaining.

Then on Wednesday, Icahn upped the ante, offering to pay $80 per share, a bid that the company said it would consider in due course.

No means no, mister
In addition, Clorox has also adopted a shareholder rights agreement, also known as a "poison pill," to protect itself from future unwanted advances. This agreement would end up significantly penalizing any person or group that acquires 10% or more of outstanding shares without board approval, by giving all other shareholders the right to buy more shares at a substantial discount. This usually makes it prohibitively expensive for any potential suitors to proceed without board approval. Icahn now has a claim on 9.37% of outstanding shares, according to Capital IQ.

Poison pills typically aren't shareholder-friendly, although they can be in some instances. You just have to trust that the board and management are fulfilling their fiduciary duties to the shareholders and aren't putting their interests first.