Margin (Initial, Variation) The capital to be provided in advance or during the term of the contract in order to be able to trade a financial instrument (future) on the stock exchange. It serves as security in the event of an unfavourable position. The initial margin serves to cover a possible loss in value in the period between two margin calls (usually a daily loss). The variation margin covers the change in value that has occurred. Margins often only accrue once a certain credit limit has been exceeded, also known as maintenance margin.