The isolated margin mode is supported on Poloniex, under which futures positions operate independently with separate PnL, margin in use, and margin rate, ensuring no interference between them.

Initial Margin 

Initial Margin is the minimum amount when traders open a position, also called Cost.

Initial margin = Order value * Initial margin rate

The actual trading fee will be charged when the order is executed and calculated based on the execution price.

Maintenance Margin

Maintenance Margin is the minimum amount to hold the position.

Maintenance margin = Position value * Maintenance margin rate

When margin balance falls below the margin requirement, the position will be liquidated. Normally Maintenance Margin is half of the Initial Margin.

For example, if a trader uses 100x leverage to long 5 BTC at 5000 USDT, it requires 0.05 BTC (fees not included) as margin to open the position. If the price of the contract goes up by 1%, the trader will profit 100 times of the margin. Through the usage of margin and leverage, the trader gained a higher rate of return with less funds.

But if the price of the contract falls by 0.5% and the position is in Isolated Margin mode, the position will be liquidated and all the margins will be lost. However, the maximum loss is limited to the funds used for margin.

Traders could check each symbol's initial margin rate and maintenance margin rate at Contract Specifications.