Margin Is Not Maximum Loss

Second Officer · SO03: Money Maths: Profit, Size and Margin · About 25 minutes

Safety rule: Margin is collateral, not a stop-loss or a guarantee of the maximum amount you could lose.

Your mission today

By the end you can distinguish margin, equity, free margin and cash loss before opening a leveraged demo position.

Before you start

The account panels from SO02.1, and your SO03.2 cash-risk worksheet. All prices and account balances below are imaginary teaching figures, not actual market data.

1. Understand the problem

A deposit is not the price of the whole position

Imagine renting a car with a deposit. The deposit is not automatically the greatest amount you could owe if the car is damaged. In many leveraged trading products, margin is similarly a portion of funds reserved to support an open position.

Leverage allows the contract value to exceed the collateral. This increases sensitivity to price changes relative to your account funds. The possible loss depends on volume, instrument, market movement, execution and contractual protections. It is not simply equal to the initial margin requirement.

2. Worked example: show the loss first

Imagine a fictional account with $2,000 balance and a leveraged position requiring $300 margin. Initially, with no open P/L or other charges, equity is $2,000 and free margin is $1,700.

Now suppose the position develops a −$600 floating loss. Equity becomes $2,000 − $600 = $1,400. Assuming required margin is still $300, free margin becomes $1,400 − $300 = $1,100.

You have lost $600 of equity even though the posted margin was only $300. If the position instead had a +$100 floating gain, equity would be $2,100, before any fees. The favourable example does not remove the danger. The figures are imaginary and simplify real margin requirements.

Original Black Box Journey diagram. Imaginary training figures; not a real historical trade.

3. Apply the idea

Four account figures have different jobs

Balance records cash after realised trades and account adjustments. Equity adjusts the balance for open floating results. Used margin is the collateral currently required. Free margin is the equity left after subtracting used margin, under simplified account accounting.

Your terminal may also show a margin level, commonly equity divided by used margin times 100. A broker may apply special margin rates, hedged-position rules, conversion adjustments or different liquidation thresholds. Read your own contract. The margin level is not the same as a stop-loss distance.

4. Test the limitations

Stop-out and negative balances

A broker can have a stop-out procedure that automatically closes positions when account resources fall below stated rules. Liquidation may occur at unfavourable prices, and fast markets can jump past orderly execution.

Some jurisdictions and account arrangements provide negative-balance protection. Others do not, or the protection has limits. Never treat a generic platform advert as legal proof. Check the contracting company, the retail/professional classification and exact instrument terms.

An accepted stop order also cannot guarantee execution at the requested price during every gap.

5. Record a defensible decision

Stress before adding another position

Look at all open contracts, not just the next order. Two positions can depend on the same market factor and lose together. A small margin requirement on each does not make the combination safe.

Before entering, write a downside scenario and recompute the projected equity, free margin and total cash loss. If a stress case breaches your personal limit, the correct decision is to reduce size or skip. Do not use spare free margin as a target for how much risk to take.

6. Stress the whole account before reading free margin

Synthetic account exercise: Assume equity is $1,000, required margin is $200 and free margin is $800. A separate adverse price move causes an unrealised loss of −$300. If the margin requirement stays unchanged, equity becomes $700 and free margin becomes $500. The $200 margin was collateral, not a promised maximum loss. A forced close or price gap could produce a different result under the broker's rules.

Now add a proposed second position. If its planned loss is another $100, the account could face $400 combined adverse movement under this simplified scenario. Check correlated exposures too: two symbols driven by the same currency event are not independent just because their names differ.

Practice record: Write current equity, used margin, free margin, total stop-based price risk and a worse-fill scenario. Then mark APPROVE or SKIP. If the contract or margin rules are unknown, do not treat available buying power as permission to take the risk.

Common mistake

Saying 'only $300 margin was used, so only $300 can be lost' confuses collateral with market exposure. In the example, losses exceeded the margin already. Fix it by computing risk from size and adverse price movement.

Plain-English glossary

• Margin: Collateral required to support some leveraged positions.
• Leverage: Exposure relative to the funds required to maintain it.
• Balance: Realised account cash balance.
• Equity: Balance adjusted for floating position results.
• Free margin: Equity less used margin in a simplified account.
• Stop-out: Broker action to reduce exposure under its margin rules.

Try it yourself

Record balance, equity, used and free margin in three imaginary scenarios: flat, losing and profitable. Then add a second correlated position and recompute total downside. State which broker rules you must verify before drawing a live conclusion. Keep the original inputs and your final result together in your student journal.

What you can now do

• Explain the difference between margin and loss.
• Calculate equity and simplified free margin.
• Stress-test simultaneous exposure before adding a position.

Next lesson

SO03.4 · Costs: Spread, Commission, Swap and Slippage. Read it after completing the worksheet above, not just after reading the headings.