What Is Margin?

In finance, the margin is the collateral that an investor has to deposit with their broker or an exchange to cover the credit risk the holder poses for the broker or the exchange. An investor can create credit risk if they borrow cash from the broker to buy financial instruments, borrow financial instruments to sell them short, or enter into a derivative contract.

Buying on margin occurs when an investor buys an asset by borrowing the balance from a broker. Buying on margin refers to the initial payment made to the broker for the asset; the investor uses the marginable securities in their brokerage account as collateral

In a general business context, the margin is the difference between a product or service's selling price and the cost of production, or the ratio of profit to revenue. Margin can also refer to the portion of the interest rate on an adjustable-rate mortgage (ARM) added to the adjustment-index rate.

Key Takeaways

  • Margin is the money borrowed from a broker to purchase an investment and is the difference between the total value of an investment and the loan amount.
  • Margin trading refers to the practice of using borrowed funds from a broker to trade a financial asset, which forms the collateral for the loan from the broker.
  • A margin account is a standard brokerage account in which an investor is allowed to use the current cash or securities in their account as collateral for a loan.
  • Leverage conferred by margin will tend to amplify both gains and losses. In the event of a loss, a margin call may require your broker to liquidate securities without prior consent.
1:40

Margin

Understanding Margin

Margin refers to the amount of equity an investor has in their brokerage account. "To margin" or "buying on margin" means to use money borrowed from a broker to purchase securities. You must have a margin account to do so, rather than a standard brokerage account. A margin account is a brokerage account in which the broker lends the investor money to buy more securities than what they could otherwise buy with the balance in their account.

Using margin to purchase securities is effectively like using the current cash or securities already in your account as collateral for a loan. The collateralized loan comes with a periodic interest rate that must be paid. The investor is using borrowed money, or leverage, and therefore both the losses and gains will be magnified as a result. Margin investing can be advantageous in cases where the investor anticipates earning a higher rate of return on the investment than what he is paying in interest on the loan.

For example, if you have an initial margin requirement of 60% for your margin account, and you want to purchase $10,000 worth of securities, then your margin would be $6,000, and you could borrow the rest from the broker.

Buying on Margin

Buying on margin is borrowing money from a broker in order to purchase stock. You can think of it as a loan from your brokerage. Margin trading allows you to buy more stock than you'd be able to normally. To trade on margin, you need a margin account. This is different from a regular cash account, in which you trade using the money in the account.

By law, your broker is required to obtain your consent to open a margin account. The margin account may be part of your standard account opening agreement or may be a completely separate agreement. An initial investment of at least $2,000 is required for a margin account, though some brokerages require more. This deposit is known as the minimum margin.

Once the account is opened and operational, you can borrow up to 50% of the purchase price of a stock. This portion of the purchase price that you deposit is known as the initial margin. It's essential to know that you don't have to margin all the way up to 50%. You can borrow less, say 10% or 25%. Be aware that some brokerages require you to deposit more than 50% of the purchase price. (Related: Buying on Margin Explainer Video.)

You can keep your loan as long as you want, provided you fulfill your obligations such as paying interest on time on the borrowed funds. When you sell the stock in a margin account, the proceeds go to your broker against the repayment of the loan until it is fully paid.

There is also a restriction called the maintenance margin, which is the minimum account balance you must maintain before your broker will force you to deposit more funds or sell stock to pay down your loan. When this happens, it's known as a margin call. A margin call is effectively a demand from your brokerage for you to add money to your account or close out positions to bring your account back to the required level. If you do not meet the margin call, your brokerage firm can close out any open positions in order to bring the account back up to the minimum value. Your brokerage firm can do this without your approval and can choose which position(s) to liquidate.

In addition, your brokerage firm can charge you a commission for the transaction(s). You are responsible for any losses sustained during this process, and your brokerage firm may liquidate enough shares or contracts to exceed the initial margin requirement.

Special Considerations

Because using margin is a form of borrowing money it comes with costs, and marginable securities in the account are collateral. The primary cost is the interest you have to pay on your loan. The interest charges are applied to your account unless you decide to make payments. Over time, your debt level increases as interest charges accrue against you. As debt increases, the interest charges increase, and so on. Therefore, buying on margin is mainly used for short-term investments. The longer you hold an investment, the greater the return that is needed to break even. If you hold an investment on margin for a long period of time, the odds that you will make a profit are stacked against you.

Not all stocks qualify to be bought on margin. The Federal Reserve Board regulates which stocks are marginable. As a rule of thumb, brokers will not allow customers to purchase penny stocks, over-the-counter Bulletin Board (OTCBB) securities, or initial public offerings (IPOs) on margin because of the day-to-day risks involved with these types of stocks. Individual brokerages can also decide not to margin certain stocks, so check with them to see what restrictions exist on your margin account.

A Buying Power Example

Let's say that you deposit $10,000 in your margin account. Because you put up 50% of the purchase price, this means you have $20,000 worth of buying power. Then, if you buy $5,000 worth of stock, you still have $15,000 in buying power remaining. You have enough cash to cover this transaction and haven't tapped into your margin. You start borrowing the money only when you buy securities worth more than $10,000. 

Note that the buying power of a margin account changes daily depending on the price movement of the marginable securities in the account.

Other Uses of Margin

Accounting Margin

In business accounting, margin refers to the difference between revenue and expenses, where businesses typically track their gross profit margins, operating margins, and net profit margins. The gross profit margin measures the relationship between a company's revenues and the cost of goods sold (COGS). Operating profit margin takes into account COGS and operating expenses and compares them with revenue, and net profit margin takes all these expenses, taxes, and interest into account.

Margin in Mortgage Lending

Adjustable-rate mortgages (ARM) offer a fixed interest rate for an introductory period of time, and then the rate adjusts. To determine the new rate, the bank adds a margin to an established index. In most cases, the margin stays the same throughout the life of the loan, but the index rate changes. To understand this more clearly, imagine a mortgage with an adjustable rate has a margin of 4% and is indexed to the Treasury Index. If the Treasury Index is 6%, the interest rate on the mortgage is the 6% index rate plus the 4% margin, or 10%.

What does it mean to trade on margin?

Trading on margin means borrowing money from a brokerage firm in order to carry out trades. When trading on margin, investors first deposit cash that then serves as collateral for the loan, and then pay ongoing interest payments on the money they borrow. This loan increases the buying power of investors, allowing them to buy a larger quantity of securities. The securities purchased automatically serve as collateral for the margin loan.

What is a margin call?

A margin call is a scenario in which a broker who had previously extended a margin loan to an investor sends a notice to that investor asking them to increase the amount of collateral in their margin account. When faced with a margin call, investors often need to deposit additional cash into their account, sometimes by selling other securities. If the investor refuses to do so, the broker has the right to forcefully sell the investor’s positions in order to raise the necessary funds. Many investors fear margin calls because they can force investors to sell positions at unfavorable prices.

What are some other meanings of the term margin?

Outside of margin lending, the term margin also has other uses in finance. For example, it is used as a catch-all term to refer to various profit margins, such as the gross profit margin, pre-tax profit margin, and net profit margin. The term is also sometimes used to refer to interest rates or risk premiums.