It's fun to see what companies professional investors are interested in. Fortunately, courtesy of the Securities and Exchange Commission, it's not that hard to take a peek at their holdings.

Earlier this week, billionaire investor Steven A. Cohen reported that, through his hedge fund, SAC Capital Advisors, and associated entities, he has upped his stake in Pharmion (NASDAQ:PHRM) to 7.1%.

His previous SEC declaration in March said that Cohen owned a 5.1% stake in the company. It isn't clear how long he's owned the additional shares, so it's possible that he and the other hedge fund investors made a ton of cash, since Pharmion has more than doubled since then.

Much of that increase was because Celgene (NASDAQ:CELG) announced last month it was acquiring Pharmion for $2.9 billion. Of course, positive trial results for its Vidaza drug back in August helped a lot, too.

Perhaps more interesting than the fact that Cohen increased his ownership is that he made a 13-D filing, the form used by active investors, which varied from the form for passive investors used last March. The most recent filing did say that the purchases were made as an investment and not to influence the company's direction.

Still, with the close of the purchase not happening until later next year, it'll be interesting if Cohen tries to influence the deal to get more money out of Celgene or perhaps another buyer. One has to wonder if Eisai's recent acquisition of MGI Pharma (NASDAQ:MOGN) -- one of Pharmion's competitors -- had anything to do with the decision to add to its position.

Frankly, though, I'd look elsewhere than Pharmion, as there are plenty of good bets for biotech in 2008.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.