Yahoo chairman Roy Bostock has hit back at Carl Icahn, following the investor's attempts to overthrow the company's board of directors.

In an open letter to the billionaire, Bostock defended the current board's decision to turn down Microsoft's takeover bid. He also attacked Icahn's decision to put forward 10 nominees as potential new management for the firm.

"We do not believe it is in the best interests of Yahoo stockholders to allow you and your hand-picked nominees to take control of Yahoo for the express purpose of trying to force a sale of Yahoo to a formerly interested buyer who has publicly stated that they have moved on," he wrote.

Bostock also re-affirmed that Yahoo remains open to the possibility of a future deal with Microsoft and any other interested organisations.

"Please may I remind you that there is currently no acquisition offer on the table from that company or any other party. That said, we have been crystal clear in our stance that we have been and remain willing to consider any proposal from any party including Microsoft if it offers our stockholders full and certain value."