Shorting a stock is not in any way shape or form an option trade. Put options are a right to sell a stock at a particular price, betting that the price will go down. It has an expiration date, and if the stock hasn't reached that price and you are holding when it expires, you lose the entire amount invested. This is some fraction of the stock price, depending on how far away the stock is. You buy 1 contract for the right to sell 100 shares. If you short the stock, you borrow and as described earlier you have to pay interest until you close it out. Further, lets say the stock was at $10 per share, then balloons to $100. You will have to pay the difference ($90 per share) to get out of it. On top of the interest. Short positions don't expire, it is the interest that presses you to close out at a loss, even if you think the price eventually has to come down. There are a few more nuances, but that's the gist of it.