Margin (finance)

In finance, a margin is collateral that the holder of a financial instrument has to deposit to cover some or all of the credit risk of their counterparty (most often their broker or an exchange). This risk can arise if the holder has done any of the following:

The collateral for a margin account can be the cash deposited in the account or securities provided, and represents the funds available to the account holder for further share trading. On United States futures exchanges, margins were formerly called performance bonds. Most of the exchanges today use SPAN ("Standard Portfolio Analysis of Risk") methodology, which was developed by the Chicago Mercantile Exchange in 1988, for calculating margins for options and futures.

Margin account

A margin account is a loan account by a share trader with a broker which can be used for share trading. The funds available under the margin loan are determined by the broker based on the securities owned and provided by the trader, which act as collateral over the loan. The broker usually has the right to change the percentage of the value of each security it will allow towards further advances to the trader, and may consequently make a margin call if the balance available falls below the amount actually utilised. In any event, the broker will usually charge interest, and other fees, on the amount drawn on the margin account.