To keep the positions open, traders are required to hold a percentage of the value of their position, i.e., the Maintenance Margin percentage. If a trader fails to fulfill the maintenance requirement, his/her position will be taken over by the liquidation engine and gets liquidated, and the maintenance margin will be lost.
Traders could check the maintenance margin percentage at Contract Specifications
The calculation of the maintenance margin is based on the average entry price and the position leverage. Traders shall take notice to the price gap of the liquidation price and the mark price. If the mark price reaches the liquidation price, the position will be taken over by the liquidation engine and get liquidated.
If the account balance falls into a negative balance, the insurance funds will be applied to cover the cost, but if the insurance funds is not sufficient to cover the extra cost of the liquidation, the ADL will be triggered therefore guarantee that the trader will only lose the fixed amount of margin.