Margin balance is the amount of money available in a margin account. A margin account is a type of brokerage account that allows an investor to borrow money from the broker to buy securities. The investor can use the borrowed funds, along with their own money, to buy securities. The margin balance is the total amount of money in the account, including any borrowed funds.

The margin balance is important because it determines how much an investor can borrow. The amount of money that can be borrowed is known as the "buying power" of the margin account. The buying power is typically expressed as a ratio, such as 2:1 or 4:1, which indicates that the investor can borrow up to twice or four times the amount of their margin balance.

Margin balance refers to the amount of money an investor has borrowed from a brokerage to purchase securities on margin, minus the equity in their margin account. When trading on margin, investors use borrowed funds to leverage their investments, allowing them to buy more stocks than they could with their own capital alone. The margin balance is the total debt owed to the broker, which fluctuates based on market performance and additional trades. If the account value drops below the broker's required maintenance margin, the investor may face a margin call, requiring them to deposit more funds or sell assets to cover the shortfall. Properly managing margin balance is crucial to avoid excessive losses and forced liquidation of positions. Investors should use margin cautiously, as it amplifies both gains and risks.