Major Yahoo! investor Daniel Loeb on Friday called for co-founder Jerry Yang to be ousted from the floundering Internet firm's board of directors.

Loeb called for the purge as he notified the US Securities and Exchange Commission that his investment firm Third Point has become the second largest shareholder in Yahoo! and owns 5.23 percent of its shares.

Loeb's crusade against Yang came as Yahoo! reportedly courted suitors interested in buying the pioneering Internet firm that faded from glory after being trounced by Google in the online search arena.

The investor expressed concern regarding news reports that Yang might be among those maneuvering to buy Yahoo!

"Given his ineptitude in dealing with the Microsoft negotiations to purchase the Company in 2008; it is now clear that he is simply not aligned with shareholders," Loeb said in a letter to the board of directors.

"At a bare minimum, Mr Yang must declare whether he is a buyer or a seller -- he cannot be both."

Loeb demanded that Third Point be awarded board seats vacated by Yang and chairman Roy Bostock, or be given two newly created seats.

"Yahoo's board of directors' objective is, and always has been, to serve the best interests of all the company's shareholders," the company said in a statement.

"The board's comprehensive strategic review is being properly managed for the benefit of all shareholders."

Yang and the other members of the board of directors are conducting a "strategic review process" to determine the company's path, according to Yahoo!

The company declined to comment on reports it is on the auction block.

"News reports based on rumor and speculation are just that," Yahoo! said.

"The board's comprehensive strategic review process is still underway, with a wide range of options under active consideration."

Yahoo! has yet to replace fired chief executive Carol Bartz, who blasted the company's board after being shown the door in September.

Top hedge fund manager Loeb listed the hiring of Bartz as among Yahoo! board blunders and called for "sweeping changes" after she was ousted.

"From the failed Microsoft sale negotiations, to a subsequent bungled and disappointing search deal with Microsoft, through a series of misguided CEO selections, and most recently the Alipay debacle, this board's failures have destroyed value for all Yahoo! stakeholders," Loeb said at the time.

Loeb's filing with the SEC contended the intrinsic value of Yahoo! was more than $20 per share. Yahoo! stock was trading at $15.32 on the NASDAQ late Friday.

Microsoft was publicly humiliated nearly four years ago when Yang rejected a generous bid for Yahoo! at $31 a share, giving it a $44.6 billion valuation.

When Microsoft raised the offer to $33 a share, a valuation of more than $47 billion, Yang still said it was too little.