Jim Simons acquired 1.27 Million Abiomed shares worth $482 Million. That's 0.62% of their equity portfolio (17th largest holding). The investor owns 2.83% of the outstanding Abiomed stock. The first Abiomed trade was made in Q2 2013. Since then Jim Simons bought shares twenty more times and sold shares on sixteen occasions. The stake costed the investor $260 Million, netting the investor a gain of 85% so far.