Maintenance Margin is the minimum margin required to continue holding a position.

For perpetual contracts, the maintenance margin base rate is 0.5% for BTC and 1% for ETH, EOS and XRP of the contract value when opening a position. It will increase or decrease accordingly as risk limit changes.

Liquidation occurs when the isolated margin for the position is less than its maintenance margin level.

For example:

A trader buys 12,000 BTCUSD contracts at 8,000 USD with 50x leverage.

The isolated margin used for this position is:

Initial margin

= 12,000/(8,000*50)

= 0.03 BTC

Maintenance Margin

= (12,000/8,000)×0.5%

= 0.0075 BTC

This means that this position could take an unrealized loss of up to 0.0225 BTC (0.03 BTC -0.0075 BTC) before the occurrence of liquidation. It is thus very important for traders to be constantly aware of the margin level on their positions.

USDT contracts: 

Initial Margin = Contract Value / Leverage

Maintenance Margin = Contract Value × Maintenance Margin Rate

Contract Value (Position Value) = Quantity × Entry Price