What Is Short Selling and How Does It Work?

Short selling is the practice of selling shares you do not own, with the intention of buying them back later at a lower price. The mechanics work like this: you borrow shares from your broker, sell them immediately at the current market price, and then hope the price drops so you can buy them back cheaper and return them to the lender. The difference between your selling price and your buyback price is your profit. If you short a stock at $100 and it falls to $70, you make $30 per share minus borrowing costs and fees.

The critical risk of short selling is that losses are theoretically unlimited. When you buy a stock, the most you can lose is your entire investment — the stock goes to zero. But when you short, the stock can rise indefinitely. If you short at $100 and the stock rises to $300, you have lost $200 per share — twice your original position size. This asymmetric risk is why short selling requires a margin account and your broker can force you to close your position (a margin call) if losses mount. Short squeezes — where rising prices force short sellers to buy back shares, pushing prices even higher — have caused spectacular losses, as seen with GameStop in 2021.

For most retail investors, short selling is not advisable as a primary strategy. The risk-reward profile favors being long stocks over the long term because markets have a historical upward bias. However, understanding short selling is valuable because short interest data — the percentage of a company's shares sold short — is a useful sentiment indicator. High short interest can signal that sophisticated investors see problems, but it can also set up short squeeze opportunities. StoxPulse tracks insider trading and sentiment signals that often precede the same price movements short sellers are betting on.