NEW YORK ( TheStreet) -- Carl Icahn raised his bid for Clorox ( CLX) to $80 a share from the bid of $76.50 a share he made late last week for the bleach and cleaning products maker. On Monday, Clorox said Icahn's offer of $76.50 a share, valuing the company at about $10 billion, "substantially" undervalued the company. Icahn is Clorox's largest shareholder. >>View Carl Icahn's Portfolio Icahn, in a letter to Clorox's board on Wednesday, said he would put up $6.2 billion of his own money to put to rest any credibility questions about his offer. Share of Clorox were up 3.3% to $74.96 in premarket trading Wednesday. -- Written by Joseph Woelfel >To contact the writer of this article, click here: Joseph Woelfel >To submit a news tip, send an email to: firstname.lastname@example.org.