Street Explained: Beware short-covering rallies

A trader works on the floor of the New York Stock Exchange.
Brendan McDermid | Reuters

The market rallied this week, but one group of stocks has really surged: heavily shorted stocks, including commodity companies such as Freeport McMoRan and Transocean and industrials like Deere.

In an exclusive video for CNBC Pro subscribers, Bob Pisani explains what shorting a stock means and why you must keep an eye on names that are being heavily shorted by hedge funds.

Watch the video below for all the highlights: