An order by a brokerage for an account holder to deposit more cash or securities into a margin account when the value of the cash and securities currently in it falls below some defined percentage. Every margin account has a maintenance margin requirement, which is money or securities an investor must keep in his/her margin account in order to be able to borrow from the brokerage. FINRA requires that the maintenance margin must be at least 25% of the amount borrowed, while some brokerages require maintenances of up to 50%. If the maintenance margin falls below this, the account may be subject to a maintenance call. If the account holder is not able to make the necessary deposit, he/she must close out enough positions in order to make the deposit, or risk the account becoming blocked. A maintenance call is a form of a margin call.
A call to an investor for additional funds when the market value of securities in the investor's margin account has fallen to the point that the investor's equity (that is, the value of the securities minus the amount owed) does not meet an established minimum. If the investor does not supply the required money or securities, the firm will sell a certain number of securities sufficient to bring the account into conformity. A maintenance call is a type of margin call.