What is a margin account?
A margin account is a type of brokerage account that lets you borrow money from the broker, using the securities you already own as collateral. The borrowed money (called margin) can be used to buy additional shares, sell short, or withdraw cash against the portfolio.
Key features
- Leverage: typical retail margin is 2:1 on overnight positions and 4:1 intraday for pattern day traders, meaning a $10,000 account can hold up to $20,000 in stock overnight
- Interest charged: the broker charges interest on the borrowed balance, usually adjusted to a benchmark rate plus a spread
- Short selling enabled: selling a stock you don't own requires margin because the broker lends you shares to sell
- Immediate settlement of proceeds: no good faith violation risk on rapid round-trips
- Maintenance margin: the account must keep a minimum equity ratio. If positions drop far enough, the broker issues a margin call
- Forced liquidation: brokers can sell positions to cover a margin call, often without further notice
Risks
- Amplified losses: leverage cuts both ways. A 50% drop in a fully margined position can wipe out the account
- Interest drag: borrowing costs compound against holding periods longer than a few days
- Pattern day trader rule: four or more day trades in five business days with less than $25,000 flags the account under the PDT Rule
- Tax complications: shorting creates specific tax treatment; interest paid may be deductible against investment income
Margin is a tool, not free money. Use it sparingly and always size positions based on what you're willing to lose, not what the broker will let you buy.