Biogen (BIIB) Short Interest Ratio & Short Volume

Short interest is the volume of Biogen shares that have been sold short but have not yet been covered or closed out. As of June 15th, investors have sold 3,390,000 shares of BIIB short. 2.32% of Biogen's shares are currently sold short. Learn More on Biogen's current short interest.

The short interest ratio, also known as the "days to cover ratio", is calculated by dividing the number of shares of a stock sold short divided by its average trading volume. A short interest ratio ranging between 1 and 4 generally indicates strong positive sentiment about a stock and a lack of short sellers. A short interest ratio of 10 or greater indicates strong pessimism about a stock. BIIB shares currently have a short interest ratio of 2.0. Learn More on Biogen's short interest ratio.

As of the most recent reporting period, the following institutional investors, funds, and major shareholders have reported short positions of Biogen: Quaker Wealth Management LLC, Jane Street Group LLC, Millennium Management LLC, Cubist Systematic Strategies LLC, Caption Management LLC, Nomura Holdings Inc., Twin Tree Management LP, Eisler Capital Management Ltd., PEAK6 LLC, Walleye Trading LLC, Walleye Capital LLC, Capital Fund Management S.A., Cresset Asset Management LLC, Arrowpoint Investment Partners Singapore Pte. Ltd., Simplex Trading LLC, JPMorgan Chase & Co., Citigroup Inc., and SG Americas Securities LLC. These positions are disclosed in Form 13F filings with the Securities and Exchange Commission.

Companies that have a short interest as a percentage of float below 10% indicates positive investor sentiment and few short sellers. Stocks with a short interest percentage above 10% is considered high, suggesting some investors are pessimistic about the stock. Companies with a short interest percentage of 20% or more indicates widespread negative sentiment. 2.32% of Biogen's floating shares are currently sold short.

Biogen saw a decline in short interest during the month of June. As of June 15th, there was short interest totaling 3,390,000 shares, a decline of 10.8% from the previous total of 3,800,000 shares. Changes in short volume can be used to identify positive and negative investor sentiment. Investors that short sell a stock are betting that its price will decline in the future. An increase in short sale volume suggests bearish (negative) sentiment among investors. A decrease on short sale volume suggests bullish (positive) sentiment.

Biogen currently has issued a total of 146,530,000 shares. Some of Biogen's outstanding shares are available for trading, while others are subject to various restrictions. The public float, also referred to as floating shares or "the float", are shares that publicly owned, unrestricted and available to trade on the open market. Biogen currently has a public float of 146,250,000 shares.

2.32% of Biogen's shares are currently sold short. Here is how the short interest of companies in the industry of "biotechnology" compare to Biogen: Regeneron Pharmaceuticals, Inc. (1.95%), Alnylam Pharmaceuticals, Inc. (2.63%), Incyte Corporation (4.29%), United Therapeutics Corporation (3.66%), Neurocrine Biosciences, Inc. (3.71%), Exelixis, Inc. (7.73%), BioMarin Pharmaceutical Inc. (2.32%), Exact Sciences Corporation (4.25%), Repligen Corporation (6.38%), Halozyme Therapeutics, Inc. (9.08%),

As of the most recent reporting period, the following stocks had the largest short interest positions: SPDR S&P 500 ETF Trust ($69.26 billion), Invesco QQQ ($25.22 billion), iShares Russell 2000 ETF ($20.33 billion), iShares 20+ Year Treasury Bond ETF ($9.99 billion), MicroStrategy Incorporated ($9.12 billion), Canadian Natural Resources Limited ($6.73 billion), SPDR S&P Biotech ETF ($6.52 billion), Invesco S&P 500 Equal Weight ETF ($5.60 billion), Financial Select Sector SPDR Fund ($4.64 billion), and iShares iBoxx $ Investment Grade Corporate Bond ETF ($4.59 billion). View all of the most shorted stocks.

Short selling BIIB is an investing strategy that aims to generate trading profit from Biogen as its price is falling. BIIB shares are trading down $0.49 today. To short a stock, an investor borrows shares, sells them and buys the shares back on the public market later to return it to the lender. Short sellers are betting that a stock will decline in price. If the stock does drop after selling, the short seller buys it back at a lower price and returns it to the lender. The difference between the sell price and the buy price is the trader's profit.

A short squeeze for Biogen occurs when it has a large amount of short interest and its stock appreciates in price. This forces short sellers to cover their short interest positions by buying actual shares of BIIB, which in turn drives the price of the stock up even further.

Short interest is typically published by a stock exchange once per month. However, NASDAQ publishes a report for U.S. stocks, including BIIB, twice per month. The most recent reporting period available is June, 15 2025.