The Security and Exchange Commission is looking into a well-timed and steep ramp-up of health-care investment by Steve Cohen’s SAC Capital that netted the giant hedge fund big profits in 2007, The Wall Street Journal reports this morning. In advance of the takeover of biotechnology firm MedImmune by AstraZeneca PLC, SAC bought hundreds of thousands of shares in the company, increasing its ownership fivefold. When the merger went public, MedImmune shares jumped 18 percent — but over the previous six weeks they’d already been driven up 50 percent, suggesting that traders (including ones at SAC) may have heard rumors of the deal well in advance. SAC has not been accused of wrongdoing but is now just another arm of the SEC’s massive investigation into insider trading on Wall Street — and SAC in particular. Who will sell a baseball team to Cohen now?