Short, also known as short, short (in Hong Kong) and short (in Singapore and Malaysia), as opposed to long, refers to investors borrowing securities from securities companies and selling them without holding securities in their hands. Short position, also known as short position, short position and short selling (in Singapore and Malaysia), is contrary to long position, which means that investors borrow securities from securities companies and sell them without holding securities. Short positions must cover positions within the same day, or they cannot be delivered after the close (delivery of the securities bought by the buyer), which constitutes default delivery. Short selling is usually an operation when predicting that the market will fall. In the traditional securities market, investors will make profits when the market goes up, while shorting is a special way for investors to make profits when the market goes down. If the market falls as expected, the price difference can be earned by covering at a low price. However, if the market does not fall but rises, theoretically there is no upper limit for the price increase, and it will suffer heavy losses when covering, so it is very risky and speculative. Because of its high speculation, not every stock exchange allows short selling; Even if allowed, there are often more restrictions.