In a letter to Yahoo Chairman Roy Bostock, Icahn said he is nominating ten directors, including himself, following what was termed "irrational" actions by the board of Yahoo.

Sunnyvale-based Yahoo is on the hot seat for rejecting Microsoft's initial bid of $44.6 billion, or $31 per share.

Icahn reportedly has spent more than $1 billion to acquire about 50 million Yahoo shares -- a stake of about 3.6 percent -- in order to turn up the heat on Yahoo's board.