Federal Reserve Board Regulation T margin calls are issued when a customer makes a transaction in a margin account and does not meet the minimum initial requirement of 50% cash or loan available. This margin call is referred to as a Fed Call. The customer must increase the equity in the account by depositing additional funds and/or marginable securities. If the necessary amount of cash or securities is not deposited into the account within the specified time period, securities may be sold to meet the call, and the account may become restricted.