Billionaire activist investor Carl Icahn says he will seek to oust Yahoo chief executive Jerry Yang if he successfully gains control of yahoo's board of directors, according to the Wall Street Journal.

Icahn accused Yang and the board of being disingenuous about entertaining an offer from Microsoft from Microsoft by adopting an employee retention plan to deter a deal, Icahn said.

I'm very cynical about many of the boards and CEOs in this country, but even I am amazed at the lengths that Jerry Yang and the board went to entrench themselves in this situation, Icahn said.

Icahn is betting that shareholders will be so upset that Yahoo would not accept a $33 per share Microsoft buyout offer for the company, that they will vote to accept the investor's slate of board nominees

Icahn is betting that Yahoo shareholders will be sufficiently incensed that Yang and the current board of directors did not accept a $33 per share offer for the company that they will be willing to replace the current board with Icahn's nominees.

Shareholders are set to vote on Icahn's slate of potential directors when Yahoo holds its annual meeting on August 1.

Icahn says that Yahoo's move to put in place a retention plan could have cost Microsoft up to $2.5 billion to keep Yahoo employees, a cost that effectively deterred a deal, he said.

Icahn said he is convinced that Microsoft executives don't trust Yang and won't bid again for the company if he is leading it.