NEW YORK (TheStreet) -- Shares of Keryx Biopharmaceuticals (KERX) - Get Report are soaring by 15.22% to $6.89 on heavy trading volume early Thursday afternoon, as Seth Klarman's Baupost Groupincreased its stake in the biopharmaceutical company.

The hedge fund reported a 42.53% stake in Keryx as of May 27, according to an SEC filing, Reuters reports. Baupost Group had previously disclosed a 34.61% stake as of October 14.

About 2.30 million shares of Keryx have been traded so far today vs. its average trading volume of roughly 1.41 million shares per day.

Separately, TheStreet Ratings team rates the stock as a "sell" with a ratings score of D-.

Keryx's weaknesses include its deteriorating net income, disappointing return on equity, generally disappointing historical performance in the stock itself and generally high debt management risk.

You can view the full analysis from the report here: KERX

TheStreet Ratings objectively rated this stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this article's author.

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