NEW YORK (AP) -- Billionaire investor Carl Icahn is staying the course. The hedge fund manager increased his offer for Clorox Co. by almost 5 percent to $10.7 billion on Wednesday, two days after the consumer products maker rejected his initial bid.In a regulatory filing with the Securities and Exchange Commission, Icahn said he was boosting his offer to $80 per share from $76.50 a share, which valued the company at $10.2 billion.Clorox confirmed that it received the revised bid and said that its board, which is consulting with financial and legal advisers, would review the offer "in due course."The company's stock rose $1.77, or 2.4 percent, to close at $74.34 Wednesday.Icahn, Clorox's biggest shareholder, said in a letter to the company's board that shareholders should be allowed to decide whether to accept his offer or a potentially higher one from another suitor if it materializes. Icahn said he and the company should abide by the shareholders' decision in order to avoid a proxy fight.Icahn was at times combative in the letter and took aim at Clorox's performance."You argue that our offer is inadequate because of the future rewards shareholders will possibly reap at some date in the future from your `centennial strategy.' But you have already lowered guidance for fiscal year 2011 twice and issued disappointing guidance for fiscal year 2012, making the `centennial plan' unachievable in the near term," he wrote.Icahn Enterprises LP made its initial unsolicited bid for Clorox on Friday. Rather than urge the company to take the unsolicited offer, Icahn said Clorox should shop itself to competitors, saying it could get a better offer from U.S. competitors like Procter & Gamble, Colgate-Palmolive Co., and Kimberly-Clark Corp., or from overseas rivals like Unilever PLC, Reckitt Benckiser and Henkel AG.Clorox rejected the initial offer on Monday, saying it was too low. The company also said at the time that it was adopting a "poison pill" shareholder rights measure to try to ward off Icahn. Clorox said it was committed to its current strategy, saying its own plans are the best way to create value for its shareholders.The shareholder rights plan will take effect if a person or group acquires a 10 percent stake in Clorox in a transaction not approved by the board. If that happens, the company will issue one stock purchase right for each share outstanding as of July 28.Icahn bought a 9.4 percent stake in Clorox in December.Clorox was formed 98 years ago by five entrepreneurs selling what became the company's namesake bleach. The company has continually expanded its product line to include goods such as Burt's Bees lip balm, Glad trash bags, Brita water filters and an eclectic mix of other household products.But like its peers, Clorox is facing higher prices for materials it needs to make and transport its products, and it also has to persuade customers to keep buying as they get squeezed by higher gas and grocery prices.Icahn is known for buying and shaking up struggling companies, with mixed success. His other holdings at the end of the first quarter included the drug maker Biogen Idec Inc., movie studio Lions Gate Entertainment Corp., Motorola Solutions Inc. and power producer Dynegy Inc., according to a May 16 regulatory filing.