Maintenance margin refers to the minimum amount of equity that an investor must maintain in their margin account to avoid a margin call from their broker. The maintenance margin is typically set by the broker and is expressed as a percentage of the total value of the securities held in the account.

For example, if an investor has $10,000 worth of securities in their margin account and the maintenance margin requirement is 25%, the investor must maintain at least $2,500 in equity in their account. If the value of the securities in the account drops below a certain level, the broker may issue a margin call, requiring the investor to deposit additional funds to bring the account back up to the required maintenance margin level.

A maintenance margin is the minimum equity a trader must maintain in their margin account to keep a position open. For example, suppose a trader buys $10,000 worth of stock using $5,000 of their funds and $5,000 borrowed from a broker. If the maintenance margin is 25%, the account must maintain at least $2,500 equity.

If the stock value drops to $8,000, the trader's equity becomes $3,000 ($8,000 - $5,000 loan). Since $3,000 is above the $2,500 maintenance margin, no action is needed. However, if the stock falls further to $6,000, the equity shrinks to $1,000. This triggers a margin call, requiring the trader to deposit funds or sell assets to restore the minimum balance.