Sotheby's, a multinational company headquartered in New York, had adopted a "poison pill" last Friday. This was two days after activist investor Daniel Loeb's Third Point hedge fund had planned to increased its stake in the company. The hedge fund had also called for a management shake-up at auction house Sotheby's.

Loeb's Third Point has around USD13 billion under its management. The fund wants to replace the leadership at Sotheby's after stating that it had seen weak financial results and loss of ground to rival auction house, Christie's.

Sotheby's and its CEO and Chairman William Ruprecht had fought back after pointing to an increase at stock price. The company had also pointed out to the latest blockbuster sales such as 2012's auction of Edvard Munch's "The Scream", valued USD120 million.

The shareholder rights plan, otherwise known as the poison pill, would be triggered if any one investor, with exceptions, to acquire more than 10% of Sotheby's common shares.

The company said, "It is intended to protect Sotheby's and its shareholders from efforts to obtain control that are inconsistent with the best interests of the company and its shareholders."