NEW YORK: After several days of hostile growling, billionaire corporate raider Carl Icahn (pictured) finally leapt for Yahoo's jugular on Thursday, filing a proxy slate to remove every member of the latter's ten-strong board of directors.

He also fired off a letter to Yahoo chairman Roy Bostock accusing the board of acting "irrationally" in rejecting Microsoft's acquisition overtures.

That view, replied Yahoo ceo Jerry Yang, "reflects a significant misunderstanding of the facts about the Microsoft proposal and the diligence with which our board evaluated and responded to that proposal."

Icahn has amassed some ten million Yahoo shares with options to acquire an additional 49m, gambling that he can leverage that stock to entice Microsoft to reinstate its bid for the ailing internet portal. 

Like any good poker player, the software titan's cards remain closely pressed to its chest. But many observers think it unlikely that there has not already been some discourse between Icahn and senior Microsoft executives.

Meantime, Icahn needs to win the support of other Yahoo shareholders, set to vote on the board appointments at the firm's annual meeting on July 3.

In addition to himself, Icahn's nominees include his close associate Keith Meister, former Viacom ceo Frank Biondi, Harvard Law School Professor Lucian Bebchuk, Dallas Mavericks' owner Mark Cuban and five other investors.

Data sourced from Wall Street Journal Online; additional content by WARC staff