1, The minimum value that must be present in an account in order to continue to hold a position. The maintenance margin is typically less than the initial margin, and also differs by contract. If the account falls below the maintenance margin requirement, the account holder will receive a margin call. If he/she wishes to continue to hold the position, they will be required to restore the account to the full initial margin level (not to the maintenance margin level). Also known as the maintenance performance bond.
2, The minimum margin which an investor must keep on deposit in a margin account at all times in respect of each open contract.