If you are shorting stocks by borrowing shares of the stock from your broker, your risk to the upside is unlimited. Especially, if you get news that impacts that company either negatively or positively, in a huge way. This is how a lot of retail traders blowout their account and lose all their monies all in one trade. Don't be one of the dumb ones to find out the hard way. The way to short any stock is to buy a put option if they have options (make sure open interest is atleast 200 contracts). Not all companies have options to trade. Buying a put option, your risk on a worst case scenario, is to lose the cost of the premium, say $500. That is the absolute most you can lose. Of course, if your option drops to $250 in value, you can sell it and take that $250 and save some capital. You have lost only $250.