Jim Simons acquired 1.41 Million Abiomed shares worth $415 Million. That's 0.55% of their equity portfolio (24th largest holding). The investor owns 3.12% of the outstanding Abiomed stock. The first Abiomed trade was made in Q2 2013. Since then Jim Simons bought shares nineteen more times and sold shares on fifteen occasions. The stake costed the investor $289 Million, netting the investor a gain of 44% so far.