Short position refers to the situation that the customer's rights and interests in the investor's margin account are negative under some special circumstances. When the market situation changes greatly, if most of the funds in the investor's margin account are occupied by trading margin, and the trading direction is opposite to the market trend, it is easy to explode the position because of the leverage effect of margin trading. Under normal circumstances, under the daily liquidation system and the compulsory liquidation system, there will be no explosion of positions. However, in some special circumstances, such as when there is a gap change in the market, accounts with more reverse positions are likely to explode.

Clearance means clearance, postponement means selling all the stocks, and the stock market means selling all the stocks.