Short Interest in Biotech Firms Resumes (BIIB, GILD, ILMN, REGN)

The short interest data is out from the September 14 settlement date. By and large, short sellers have resumed their gambles on biotech firms compared to the August 31 settlement date. Short interest had waned for the most part in the two weeks before the end of August. Two notable exceptions to the resumed rise in short interest this month were Amgen

, for which shares sold short declined 2.2 percent to 12.61 million, and Pharmacyclics

, which saw short interest fall 5.7 percent to 4.91 million. Here is closer look at Biogen Idec

, Gilead Sciences

, Illumina

and Regeneron Pharmaceuticals Inc.

, which saw the largest percentage growth in short interest in the sector between the August 31 and September 14 reports.

This S&P 500 component saw short interest grow 4.8 percent to 2.22 million shares. Biogen Idec develops and markets therapies for the treatment of neurodegenerative diseases, hemophilia and autoimmune disorders. It has a market capitalization of more than $36 billion and a return on equity of nearly 22 percent. Biogen Idec sold royalty rights on a lupus drug to a Canadian fund in September. Shares are up about 36 percent year to date and reached a multi-year high Wednesday.

Shares sold short in Gilead Sciences were up 9.3 percent to 20.61 million. This maker of therapeutics for the treatment of life-threatening diseases such as HIV and hepatitis has a market cap near $50 billion. It too is an S&P 500 component, and its return on equity is more than 36 percent. The company received FDA approval of its HIV drug Stribild at the end of August. Out of 29 analysts surveyed by Thomson Reuters, 22 rate the stock at Buy or Strong Buy; none recommend selling shares.

Short interest in this maker of life science tools and integrated systems for genetic analysis increased 8.8 percent to 25.77 million shares. Short interest was 21.3 percent of the float. The long-term earnings per share (EPS) growth forecast for this San Diego-based company is almost 19 percent. Earlier this month Illumina introduced its rapid Individual Genome Sequencing (IGS) service. The share price is about 50 percent higher than at the beginning of the year, but still more than 14 percent lower than the 52-week high.

This biopharmaceutical company saw short interest in its stock rise 8.4 percent to 5.19 million shares. This Tarrytown, New York-based company develops medicines for the treatment of serious medical conditions such as cardiovascular and infectious diseases. Its long-term EPS growth forecast is about 29 percent, and its market cap is more than $13 billion. Eleven of sixteen analysts polled recommend buying shares, none recommend selling. The stock is up more than 155 percent year to date.