what triggers a margin call 
an investor is buying on margin when they pay to buy and sell securities using a combination of their own funds and money borrowed from a broker an investor s equity in the investment is equal to the market value of the securities minus the borrowed amount 1a margin call is triggered when the investor s equity as a percentage of the total market value of securities falls below a certain required level called the maintenance margin the new york stock exchange nyse and the financial industry regulatory authority finra the regulatory body for the majority of securities firms operating in the united states both require that investors maintain an equity level of 25 of the total value of their securities when buying on margin 23 some brokerage firms require a higher maintenance requirement as much as 30 to 40 margin calls can occur at any time due to a drop in account value but they re more likely to happen during periods of market volatility example of a margin callhere s an example of how a change in the value of a margin account decreases an investor s equity to a level where a broker must issue a margin call 