Margin Call

A margin call is a demand from a trading venue that a leveraged trader add collateral or reduce exposure because the account's equity has fallen below the maintenance margin required for its open positions. In traditional markets the call is often a message with hours to respond; on crypto venues the process is largely automated and the window can be minutes or less, because the collateral itself is volatile and often the same asset being traded. Ignoring the call, or failing to top up in time, hands the decision to the exchange's liquidation engine, which closes positions at whatever price the book offers. Margin requirements are set by the venue and can be raised without notice during stressed markets.