The Instant Margining System (IMS) uses two different margin parameters to manage the credit risk of margin accounts. Each parameter is associated with a certain margin requirement per open long or short position and triggers certain action when reached:
|INITIAL MARGIN (IM)||This is the margin that is required to open new positions. If the portfolio value of a margin account falls below IM, all open orders that would further add to the risk of this margin account are cancelled immediately. Before any new positions can be opened, additional funds must be deposited into the margin account to bring portfolio value back above IM. Alternatively, some existing positions can be closed out.|
|MAINTENANCE MARGIN (MM)||This is the margin that is required to maintain open positions. If the portfolio value of a margin account falls below MM, then the liquidation procedure begins.|
Margin parameters are described in more detail here.