Steven Cohen's position in Biogen is currently worth $536M. That's 1.28% of their equity portfolio (8th largest holding). The investor owns 2.77% of the outstanding Biogen stock. The first Biogen trade was made in Q2 2014. Since then Steven Cohen bought shares twenty more times and sold shares on 21 occasions. The stake costed the investor $485M, netting the investor a gain of 11% so far.