Used and Usable margin

when you open an account in a company that allows you to use the system marginal . you will deposit  untouchable amount of money until you decide to go into a deal . by then your account will be divided into 2 sections .

1- used margin:

its the Deposit which will be deducted in advance and its refundable deposit . it will be returned to your account after completion of the deal . Whether the transaction was successful or losing.

2- usable margin

its the amount of money that remains in your account after deduct the used margin . and this amount is The maximum amount you are allowed to lose at the deal.