If you buy 50 lots at 4000 and you calculate 25% margin, then you are operating in Man Cang, which is not allowed in TD, so you can't operate either. Generally, when you lose money and the remaining positions occupy the margin, the bank will inform you to add positions. If you don't increase your position, the bank will force the liquidation.

Forced liquidation is also called forced liquidation, which is also called being cut, cut and exploded. It refers to the situation that the customer's rights and interests in the investor's margin account are negative under some special circumstances. A short position means that the loss is greater than the margin in your account. After the company is forced to draw a tie, the remaining funds are the total funds MINUS your losses, and generally there will be a part left. Commonly used in spot gold and futures trading.