Margin Call
Definition: A demand for additional funds because of adverse price movement. Maintenance margin requirement, security deposit maintenance.

Margin Call
Definition:

(1) A request from a brokerage firm to a customer to bring margin deposits up to initial levels;

(2) a request by the clearing organization to a clearing member to make a deposit of original margin, or a daily or intra-day variation margin payment because of adverse price movement, based on positions carried by the clearing member.