An organization may trade on an Exchange either by becoming a member of the Exchange, or trading through an ExchangeBroker. The clearing principles are similar in either case
In general a trading organization engages a ClearingBroker to act on its behalf
The trading organization is required to open a margin account with the ClearingBroker, which in turn maintains a margin account with the Exchange's Clearing Bank
As the organization enters into a trading position the Exchange marks the trades to market on a daily basis, and transfers cash into or out of margin accounts based on the change of the value of the trading position since the previous day. The ClearingBroker mirrors this operation to its clients' margin accounts
Every trading organization is required to maintain an amount of cash in the margin account to cover a substantial short term loss in the value of its position. If the trading organization does not maintain this margin then the Exchange closes out the position immediately, using the margin account cash to cover any losses as a result of the close out
Payments into the margin account as a result of new trades that cause an increased open position are called Initial Margin payments
Payments into the margin account as a result of the value of trades falling are called Variation Margin payments