What Is a Margin?

A margin is the money borrowed from a brokerage firm to purchase an investment. It is the difference between the total value of securities held in an investor's account and the loan amount from the broker. Buying on margin is the act of borrowing money to buy securities. The practice includes buying an asset where the buyer pays only a percentage of the asset's value and borrows the rest from the bank or broker. The broker acts as a lender and the securities in the investor's account act 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. A margin can also refer to the portion of the interest rate on an adjustable-rate mortgage (ARM) added to the adjustment-index rate.



Understanding Margins

A margin refers to the amount of equity an investor has in their brokerage account. "To margin" or "to buy 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.

[Important: A margin is the money borrowed from a broker to buy securities; the expression "buying on margin" refers to the act of borrowing the money.]

Special Considerations

Accounting Margin

In business accounting, a 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.

What Is a Margin in Mortgage Lending?

Adjustable-rate mortgages 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%.

Key Takeaways

  • A margin refers to money borrowed from a brokerage to buy securities. "Buying on margin" is the act of borrowing money.
  • 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.
  • The collateralized loan comes with a periodic interest rate that the investor must repay to the broker.
  • Because they are using borrowed money, or leverage, the investor's profits or losses are likely to be magnified.