Margin Call
A demand by a brokerage that an investor contribute additional cash to a margin account. It is made when the value of securities purchased on margin fall to such an extent that the initial margin required when the position was opened is no longer met. If a margin call cannot be met the brokerage will sell securities held in the account until the margin requirement is met. Failure to meet a margin call can therefore result in a considerable loss. Sometimes referred to as a maintenance call.
See also: Variation Margin, Margin Requirement