Aug. 25 (Bloomberg) -- Billionaire investor Carl C. Icahn may increase his stake in Biogen Idec Inc. because he says the company is undervalued and a takeover candidate, according to a person familiar with Icahn’s thinking.The Federal Trade Commission cleared the New York investor to buy more shares in Biogen, the world’s largest maker of drugs for multiple sclerosis, according to a message posted yesterday on the agency’s Web site.
