Most of us are familiar with the idea of being able to buy and then sell a share, normally this is referred to as going ‘long’ in other words you feel it is a good share and you want to hold on to it. The opposite of this is where you sell and then buy which is going ‘short’, in other words you don’t think the stock is good and you don’t want to hold on to it so you borrow it and sell it today, buy it tomorrow (and dispose again to the original owner) and your position is set by the difference.
In a short sale a drop in the price makes you money because (for instance) if you sold today at $3.00 and bought back at $2.80 then you made 20c per share. If however, the price goes up to say $3.20 then you have to make up the difference. This is before we get into other areas like options or any derivatives. An easy …