You can find the data and charts in the “Short Interest” tab of stocks. This is the example of Bio-Reference Laboratories Inc (NASDAQ:BRLI). The stock has a short interest of 33.42%, a big drop from historical peak of 55%, as shown in the chart:
The historical institutional ownership and Insider ownership is also shown in the page:
The short interest can help us to understand some of the price drops. For instance, Weight Watchers International, Inc. (NYSE:WTW), a member of Buffett-Munger model portfolio, has seen big price declines without news. But its short interest has soared lately:
The company spent $1.5 billion last year to buy back its undervalued shares. Currently its market cap is only $1.7 billion. This is the shares outstanding of Weight Watchers:
Let’s see who will win, the short sellers or the company?