In a letter to Yahoo! Chairman Roy Bostock, Icahn -- who has purchased 59 million Yahoo! shares since May 3 -- complained about Yahoo!'s recent negotiations with Microsoft Corp (NASDAQ:MSFT), which offered to purchase Yahoo! for $47 billion.

Yahoo! directors "acted irrationally and lost faith of shareholders," Icahn wrote to Bostock, The Wall Street Journal reported.

Ichan's nominees include himself, former Viacom Inc. Chief Executive Officer Frank Biondi Jr., venture capitalist Adam Dell and Dallas Mavericks owner Mark Cuban, the Journal reported.

Ichan's shares, which he purchased after Microsoft pulled away from purchase negotiations, are valued at $1.5 billion, the Journal said.