A CFD enables you to hypothesize on when the market prices will rise or fall in a quickly moving financial market containing instruments such as shares. One benefit of CFD is that you can trade on a margin.
Here you can short (sell) when you speculate that the prices will go down or long (buy) when you think that the prices will fall.
One of the main reasons why you sell an item is to benefit from the fall in price that will result. However, you will only gain if your speculations are true. Otherwise, you may end up making a loss. These losses can, at times, be more than your deposits.
It is crucial to study the market well to know when the time is right for you to sell, otherwise, you may end up making wrong speculations, which result in losses.