The Securities and Exchange Commission is reportedly probing whether inside information allowed hedge-fund giant SAC Capital Advisors to unfairly capitalize on the $15 billion takeover of biotechnology company MedImmune in 2007.

According to The Wall Street Journal, the probe of SAC, which is run by hedge fund heavyweight Steven Cohen, is part of a broader SEC investigation into hedge fund activity in the health-care space.

SAC did not immediately respond to a request for comment, but a spokesman told the Journal:“We respond to all regulatory inquiries fully and accurately, and we are confident in our business practices, Stamford-based SAC is considered one of Wall Street’s most successful funds and manages almost $14 billion in assets.

The hedge fund’s trading activities are also reportedly the subject of an investigation by Iowa Sen. Charles Grassley and a criminal probe by prosecutors in New York.

The SEC has zeroed in on SAC Capital’s heavy buying of MedImmune ahead of its announced takeover from AstraZeneca (AZN) on April 23, 2007, which sent MedImmune’s stock soaring 18%.

As MedImmune’s stock price increased 50% in the six weeks prior to the deal, SAC significantly boosted its holdings in the company, the Journal reported. SAC’s investment increased to 796,000 shares in the first quarter of 2007, up from just 151, 000 shares in the fourth quarter of 2006. It then eliminated its stake completely at the end of 2007’s second quarter, the paper reported.

The presence of the SEC probe complicated Cohen’s recent discussions about buying a minority stake in the New York Mets, the Journal reported. Eventually the Mets tapped fellow hedge fund star David Einhorn as the team’s preferred bidder in a $200 million deal.

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