If your account falls below the brokerage firm’s maintenance requirement, the firm will make a margin call and request that you add money or securities to your margin account. If you cannot meet the margin call, your brokerage will sell your securities until your account meets maintenance margin again.

Trading on margin allows you to borrow money to buy securities, like stocks, and make larger investments. While buying on margin can increase your returns, you also face more significant risks when investing with borrowed money. Perhaps the biggest risk of margin trading is the dreaded margin call, which can force you to liquidate a lot of securities quickly—even if it’s at an enormous loss.