Short selling, or just shorting, is a special kind of financial trade that is a bet that a stock will go down, or a hedge against a stock that will go up. A short seller borrows the stock, or some other kind of investment, from a lender, and immediately sells it. Later, he buys the same amount of stock to return to the lender. If he sold the stock he borrowed for more than he paid later to buy it and return it to the lender, the short made money. Shorts can be very risky, and are for skilled investors only.