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

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