As anticipated, Carl Icahn has begun his proxy battle with Yahoo!

In an open letter to Yahoo chairman, Roy Bostock, Icahn said the board had “acted irrationally and lost the faith of shareholders and Microsoft. It is obvious that Microsoft’s bid of $33 per share is a superior alternative than Yahoo’s prospects on a stand alone basis.”

He went on to urge Yahoo! to “move expeditiously to negotiate a merger with Microsoft, thereby making a proxy fight unnecessary.”

Alongside his support from Bill Miller, Icahn’s move has further support from at least one other major shareholder, Paulson & Co. with a 3.4 percent stake in Yahoo!

But Microsoft are showing no signs of returning to the table. Yesterday, Microsoft spokesman, Frank Shaw said simply “The company has moved on”.

Its final offer of $33 wasn’t enough to satisfy Yahoo!’s co-founder and Chief Executive Jery Yang, who wanted $37 per share, even though shares had been trading at around $19 prior to that.

For the current share price, and its movement over the last 5 days, see below.

HAVE YOUR SAY: What do you think the future holds for Yahoo!? Drop me a comment…