Icahn Ups Biogen Idec Stake to 6 Percent—Bought Big on Tysabri Woes

Perhaps there was no way that Biogen Idec (NASDAQ:BIIB) would see a major drop in its stock price without activist investor Carl Icahn working his way into the storyline.

SEC documents filed Monday show that Icahn went on a Biogen stock-buying binge beginning on August 1, the day after Biogen and its partner, Ireland’s Elan, reported that two multiple sclerosis patients taking their drug Tysabri had developed the rare and often fatal brain infection progressive multifocal leukoencephalopathy, or PML. Between then and August 11, as Biogen’s stock plummeted more than 25 percent to a one-year low of $49.60, Icahn through various entities purchased about 5 million shares of Biogen common stock, upping his stake in the company from 4.3 percent to 6 percent in the process.

Icahn’s big stock grab could signal his continued interest in pushing for a sale of the Cambridge, MA, biotech firm, which was unable to find a buyer late last year after being pushed by its maverick investor into investigating a sale. In June, Biogen fended off an attempt by Icahn to win three board seats at the company’s annual meeting. Now, it seems apparent, the battle is far from over.

Biogen’s stock was up $0.72 (1.4 percent) this morning, at $51.47.

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