What is Margin Trading?

Margin trading is the practice of borrowing money from your brokerage to buy more securities than your cash balance would allow, amplifying both potential gains and potential losses.

Margin trading involves borrowing money from your brokerage firm to purchase more securities than you could afford with your own funds. The securities in your account serve as collateral for the loan. Margin amplifies your buying power — but it equally amplifies your losses, and it comes with borrowing costs.

A margin account is required for many advanced trading strategies, including short selling, options trading, and day trading.

How Margin Works

When you open a margin account and are approved for margin borrowing, your brokerage extends a credit line based on the value of your holdings. The initial margin requirement set by FINRA is 50% — meaning you must put up at least 50% of a purchase in your own cash; the brokerage provides the other 50%.

Example:

• You want to buy $20,000 of stock
• With 50% margin, you put up $10,000 of your own money and borrow $10,000
• If the stock rises 20% to $24,000, your profit is $4,000 on your $10,000 investment — a 40% return (vs. 20% without margin)
• If the stock falls 20% to $16,000, your loss is $4,000 on $10,000 — a 40% loss

Margin Interest

Borrowing on margin is not free. Brokerages charge margin interest on the borrowed amount, typically expressed as an annual percentage rate. Rates vary by brokerage and loan size, but often range from 5% to 12%+ per year. This cost accrues daily and reduces any gains (or deepens any losses) over time.

Margin Calls

A margin call is one of the most feared events in trading. It occurs when the value of your account falls below the brokerage's maintenance margin requirement (typically 25–30% of the total position value).

When this happens, the brokerage will demand that you:

1. Deposit more cash or securities to bring the account back above the requirement, or
2. Sell positions immediately — often at the worst possible time

In fast-moving markets, a margin call can wipe out an account before you even have a chance to act. The brokerage has the right to liquidate your positions without notice.

Margin Trading Risks

• Amplified losses — Leverage works both ways; a 50% margin position doubles your percentage loss on a declining stock
• Margin calls — Forced selling at market lows can lock in devastating losses
• Interest costs — Ongoing borrowing costs erode returns over time
• Volatility risk — Even short-term price swings can trigger margin calls on leveraged positions

Margin trading is not suitable for most retail investors. It's most commonly used by experienced active traders, institutions, and short sellers. Many financial advisors recommend avoiding margin altogether for long-term investment portfolios.

Margin vs. Buying Power in a Cash Account

In a standard cash account, you can only invest money you've actually deposited. You can't short sell or trade on margin. While this limits potential returns, it also prevents the kind of catastrophic losses that can occur when leveraged positions move sharply against you.