10 Most-Shorted Biotech Stocks of 2013

BOSTON ( TheStreet) -- Here's a list of 10 bio-pharma stocks with the highest short interest as we near the mid-point of 2013, according to S&P Capital IQ. Many of the stocks on this list won't surprise anyone because they've been bull-bear battlegrounds for years. You might be surprised by the stock with the highest short interest today, so read on.

10. InterMune ( ITMN)

Short interest: 22% of float. ITMN Chart ITMN data by YCharts

Shorts say: The European commercial launch of Esbriet is still a slow work in progress. Competition could negatively impact InterMune next year when Boehringer Ingelheim is expected to announce results from phase III studies of nintedanib. Then there's the uncertainty surrounding InterMune's own U.S.-based phase III study of Esbriet -- results are also expected next year.

9. Hyperion Therapeutics ( HPTX)

Short interest: 26% of float ^NBI Chart ^NBI data by YCharts

Shorts say: Can Hyperion really get away with charging $295,000 per year for Ravicti as a therapy for urea cycle disorders, even if it's more convenient than the less expensive alternative, Buphenyl?

8. Arena Pharmaceuticals ( ARNA)

Short interest: 26.5% of float ^NBI Chart ^NBI data by YCharts

Shorts say: Belviq is a weak weight-loss drug. The commercial launch will be disappointing.

7. Sunesis Pharmaceuticals ( SNSS)

Short interest: 26.5% of float ^NBI Chart ^NBI data by YCharts

Shorts say: The phase III study of vosaroxin in acute myeloid leukemia will fail. The decision to upsize the study last September was a negative tell. Top-line results expected in the first half of 2014.

6. Synta Pharmaceuticals ( SNTA)

Short interest: 27% of float ^NBI Chart ^NBI data by YCharts

Shorts say: Synta designed the ongoing phase III lung cancer study of ganetespib around dubious, data-mined patient subgroup data. Like nearly all of these stories, the ending is tragic.

5. MannKind ( MNKD)

Short interest: 29% of float ^NBI Chart ^NBI data by YCharts

Shorts say: Inhaled insulin? Really? Bwhahahaha!

4. Ziopharm Oncology ( ZIOP)

Short interest: 33% of float ^NBI Chart ^NBI data by YCharts

Shorts say: R.J. Kirk is full of $%^&.

3. Dendreon ( DNDN)

Short interest: 35% of float ^NBI Chart ^NBI data by YCharts

Shorts say: Going out of business.

2. Spectrum Pharmaceuticals ( SPPI)

Short interest: 37% of float ^NBI Chart ^NBI data by YCharts

Shorts say: Is Raj still CEO? He is? Short!

And the most highly shorted biotech stock in 2013 is...

1. Sarepta Therapeutics ( SRPT)

Short interest: 37.5% of float ^NBI Chart ^NBI data by YCharts

Shorts say: No eteplirsen accelerated approval.

-- Reported by Adam Feuerstein in Boston.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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