Two features sit quietly in most brokerage accounts, offered as if they were ordinary tools: borrowing money to invest, and betting that something will fall. Margin and short selling are both legitimate mechanisms used by professionals. They also share a characteristic that makes them categorically different from normal investing — both can lose you more than you put in. That asymmetry deserves to be understood before either is used.
What is buying on margin?
Buying on margin means borrowing money from your broker to buy more investments than your own cash allows, using your account as collateral. If you have a certain amount and borrow against it, you control a larger position — so gains are magnified. So are losses, and that's the part the pitch tends to underplay. You also pay interest on the borrowed money, which is a constant drag whether the position goes your way or not.
The margin call
Here's the mechanism that hurts people. If your positions fall far enough, your collateral no longer covers the loan, and the broker issues a margin call — demanding you deposit more money immediately. If you can't, the broker can sell your positions, potentially at the worst possible moment, to recover their loan. Note what this means: leverage removes your ability to simply wait out a downturn. An unleveraged investor can hold through a crash and recover; a margined one can be forcibly sold at the bottom and never participate in the rebound. The bear market advice to hold and keep contributing quietly assumes you weren't leveraged.
What is short selling?
Short selling is betting an asset will fall. Mechanically, you borrow shares, sell them at the current price, and hope to buy them back cheaper later, returning them and pocketing the difference. If the price falls, you profit. If it rises, you lose — and here's the structural problem.
| Buying a stock | Shorting a stock | |
|---|---|---|
| Maximum loss | 100% — it can only fall to zero | Theoretically unlimited — price can rise indefinitely |
| Maximum gain | Unlimited | Capped — the stock can only reach zero |
| Time | Works in your favour long-term | Works against you — borrowing costs accrue |
Read that first row again. When you buy, your downside is bounded and your upside isn't. When you short, it's exactly inverted — your gain is capped and your loss theoretically isn't, because there's no ceiling on how high a price can go. That's a fundamentally unfavourable risk shape, and it's why short squeezes can be so destructive: a rising price forces short sellers to buy back, pushing the price higher still, forcing more buying.
Why the odds are stacked against retail use
Beyond the mechanics, two structural facts matter. Markets have historically trended upward over long periods, so shorting means betting against that drift while paying borrowing costs the entire time. And leverage compresses your margin for error — a position that would have been a temporary paper loss becomes a forced, permanent one. Combine that with the reality in why most active traders lose money, and you have tools that amplify an already difficult game. If either is ever used, it demands ironclad risk control and a written plan, not instinct.
The honest verdict
For the overwhelming majority of people building wealth, neither margin nor short selling belongs anywhere near their portfolio. Long-term investing in diversified assets works precisely because time and compounding are on your side — advantages that leverage and shorting both surrender. Professionals use these tools within sophisticated risk frameworks, often for hedging rather than speculation. Using them because a broker made them available, or because a stock "obviously" looks overvalued, is how ordinary investors turn a recoverable setback into a permanent loss. There is no shame in simply not using them.
Frequently asked questions
Can you lose more than you invest with margin? Yes — that's the defining risk. If leveraged positions fall far enough, losses can exceed your deposit, and a margin call can force liquidation at the worst time. It also removes your ability to simply wait out a downturn.
What is a margin call? A demand from your broker for more funds when your collateral no longer covers the borrowed amount. If you can't meet it, the broker can sell your positions — potentially at the bottom of a decline — to recover the loan.
Why is short selling considered risky? Because the risk shape is inverted: your maximum gain is capped (a price can only fall to zero) while your loss is theoretically unlimited (a price can rise indefinitely). Borrowing costs accrue over time, and short squeezes can force losses rapidly.
Should beginners use margin or short selling? Generally no. Both amplify risk in an already difficult activity and can produce losses beyond your deposit. Long-term diversified investing works because time and compounding favour you — advantages both of these tools give away.
The bottom line
Margin borrows money to amplify positions, and short selling bets on declines — both can lose more than you put in. Margin removes your ability to hold through a downturn by exposing you to forced liquidation; shorting inverts the normal risk shape so your upside is capped and your downside isn't. They're real tools with legitimate professional uses, and for almost everyone building wealth, the right amount to use is none.
Everything about these tools comes back to risk — understanding it, sizing it, and surviving it. The Asymmetric Trader's Playbook ($29, reg. $39) is a risk-first framework built on exactly that: defined risk, position sizing, and living to trade another day.
This article is general financial education, not financial advice or a recommendation to trade. Margin and short selling carry substantial risk, including losses exceeding your deposit, and aren't suitable for most people. Consult a qualified professional.