Margin Accounts: Borrowing Money to Invest
A margin account allows you to borrow money from your broker to buy securities, using your existing holdings as collateral. Regulation T allows borrowing up to 50% of the purchase price. In 2024, investors held approximately $800 billion in margin debt. Margin interest rates range from 5% (Interactive Brokers) to 12% (E*TRADE).
Margin accounts are the gateway to leveraged investing. Instead of risking only your capital, you borrow additional funds to increase your position size. If a stock rises 10%, a 2x leveraged margin position would gain 20% (minus interest costs). If it falls 10%, you lose 20%. The leverage cuts both ways. The broker lends you money at a stated interest rate (the "margin rate"), which typically floats with the broker's cost of funds (SOFR or the Fed funds rate) plus a spread. Margin loans are "callable" — the broker can demand repayment at any time, though in practice this only happens when the collateral's value falls below the maintenance requirement.
Opening a margin account requires signing a margin agreement (which includes arbitration clauses) and meeting the minimum equity requirement — typically $2,000 for most brokers (FINRA minimum). Some brokers have higher minimums. Once open, you can borrow against most securities. The "loan value" varies: most stocks have 50% loan value (you can borrow 50% of the market value), Treasury bonds have 95%+ loan value, volatile stocks may have 25% to 30%, and some securities (penny stocks, IPOs for 30 days) have 0% loan value. The broker periodically reassesses loan values based on market conditions.
Real-world example: An investor buys $50,000 of Apple stock with $25,000 of their own money and $25,000 borrowed on margin. The margin rate is 8% — annual interest of $2,000. If Apple rises 20% to $60,000, the investor's equity is $35,000 ($60,000 minus $25,000 loan) — a 40% return on $25,000 invested (before interest). If Apple falls 20% to $40,000, the equity is $15,000 ($40,000 minus $25,000) — a 40% loss. The actual return is slightly worse because of margin interest. The investor might receive a margin call at $33,333 (where equity falls below 25% of market value). At that point, they must deposit additional funds or sell stock to bring the account back into compliance.
When to Use a Margin Account
Margin accounts are useful for: short selling (you must have a margin account to short stocks), covering settlement gaps (buying securities before the cash arrives in your account), bridge loans (a margin loan can provide liquidity without selling investments — useful for a down payment while waiting for a bonus), and options trading (certain options strategies require margin). Margin is dangerous for: buying stocks you cannot afford, increasing risk beyond your risk tolerance, trying to "catch up" after losses, or making concentrated bets on volatile stocks. If you use margin, keep a significant cushion — maintain equity at 50%+ rather than the 25% minimum. Set price alerts and a personal stop-loss rule to avoid margin calls.
FAQs
What is the difference between a margin account and a cash account?
In a cash account, you must have sufficient cash in the account to pay for any purchase in full before settlement (T+1). You cannot borrow. In a margin account, the broker lends you money to buy securities, using the securities as collateral. Cash accounts are required for retirement accounts (IRAs generally cannot use margin). Margin accounts allow leverage, short selling, and certain options strategies. Most investors should start with a cash account and only open a margin account when they understand the risks and have a specific reason to borrow.
Can I lose more than my account balance on margin?
Yes. In theory, your loss on a margin trade is limited to the value of the securities — the stock cannot go below zero, so your loss is capped at the value of the securities plus margin interest. However, in very fast-moving markets, your broker may not be able to liquidate positions fast enough to prevent a "deficiency balance" — where the liquidation proceeds are less than the loan amount. In this case, you owe the broker the difference. This happened to some investors during the 1987 crash and the 2020 COVID crash. The broker has the legal right to pursue you for the deficiency. This risk is highest for volatile, illiquid stocks.
How is margin interest calculated and paid?
Margin interest is calculated daily based on the outstanding loan balance and the annual margin rate. For example, a $10,000 loan at 8% annual rate costs about $2.19 per day ($10,000 × 0.08 / 365). Interest is typically charged monthly and appears as a line item on your statement. You can pay the interest monthly or let it accrue (adding to the loan balance, increasing future interest charges). The interest is deductible against investment income (not ordinary income) on your tax return. The margin rate is negotiable — larger accounts and accounts with more assets typically receive better rates. Interactive Brokers offers the lowest margin rates (SOFR + 0.5% to 1.5%), while full-service brokers charge 3% to 5% above SOFR.