What Is Leverage in Trading?
Leverage lets you control a position larger than your account by borrowing the difference, which multiplies gains and losses by exactly the same factor. It does not improve the odds of any trade; it only changes how much of your equity each ordinary price move represents.
Leverage is the one tool in trading that does exactly what it says and is still misunderstood almost universally. It does not make a strategy better. It makes every price move bigger relative to your account, in both directions, by the same factor.
How it works
You put up part of the value and borrow the rest. Ten times leverage means £1,000 of your money controls £10,000 of the instrument. The position moves on the full £10,000; the losses come out of your £1,000.
It is symmetrical, and the symmetry is the problem. A tenfold multiplier on a good trade is attractive. The identical multiplier applies to a bad one, and losses have a property gains do not: they shrink the base that future gains are calculated on.
The requirement is not fixed. As a position moves against you, the broker wants more collateral against a loss that is now larger. That demand arrives at the worst possible moment by construction.
And when it cannot be met, the position is closed for you — at a price chosen by the mechanism rather than by your plan.
A worked example
Take the real bar sizes from this site’s shared series. The median bar range is 0.493 and the ninetieth percentile is 1.101, on a series trading around 100 — so a typical bar is about 0.49% and one bar in ten is about 1.10%.
At 2 times leverage, that typical bar is about 1% of equity. Unremarkable. A run of them is a bad week and nothing more.
At 50 times — routinely offered on currency accounts — the same ordinary bar is about 25% of equity. The ninetieth-percentile bar, which arrives one day in ten, is about 55%.
Nothing about the market changed between those two examples. The bars are identical. The only variable is a multiplier chosen in an account setting, and it converts a normal day into an account event.
Now add the run length. The longest one-way run on this series was 11 bars. At 50 times, a strategy does not need a crash, a shock or a mistake — it needs the market to do the most ordinary thing it has already been measured doing.
What it does not change
The win rate is untouched. A strategy that is right 54% of the time at 2 times leverage is right 54% of the time at 50. The multiplier operates on the size of each outcome and has no contact with the probability of it.
The expectancy per unit is untouched too. Average profit per trade, expressed as a fraction of what was risked, is the same number at every leverage. What changes is how much is being risked, which is a separate decision that leverage makes easy to take without noticing.
So leverage is never the reason a strategy works. It is a reason results are larger, in whichever direction they were already going. A losing method at 50 times is a losing method arriving sooner, and that is the whole of its effect on a negative edge.
What it does change is the number of chances you get. An edge needs a sample to show up in, and every increase in leverage reduces how many trades the account can survive to place. Past a certain multiple the strategy cannot reach the sample size its own edge requires, which is a mathematical statement rather than a cautious one.
What it costs to hold
Borrowed money is not free. Financing is charged on the full position size, not on your share of it, so a position held for weeks pays interest on an amount many times the capital committed.
And the survivable amount is set by volatility, not by what is offered. The maximum a broker permits is a legal and commercial limit. The maximum that makes sense is arithmetic, and it falls as bars get bigger.
The original data
Median bar range 0.493, ninetieth percentile 1.101, largest single bar 2.338 — on a series around 100, so roughly 0.49%, 1.10% and 2.34%.
Multiply those by the leverage and the whole argument is visible: at 10 times they are 4.9%, 11.0% and 23.4% of equity. At 50 times they are 24.7%, 55.1% and 117% — the largest single bar on record exceeds the entire account.
That last figure is the one that matters, because it is where the loss stops being capped by the money you deposited. A gap through the liquidation level does not pause for the mechanism to work.
When it fails
The characteristic failure is treating high leverage as optional headroom. The reasoning is that offered leverage is a ceiling, not an instruction, and a disciplined trader can use a fraction of it. That is correct and it is not what happens: the available size anchors the position size, the account takes a fraction of a very large number, and the resulting exposure is still several times what the strategy was tested at. The leverage was never used deliberately — it was used by comparison.
A second failure is assuming the stop caps the loss. Above a certain multiple the gap risk exceeds the deposit, so the worst case is not the stop distance — it is the overnight move.
A third is sizing in lots rather than in risk, which makes the exposure a moving target as volatility changes.
A fourth is adding to a losing leveraged position, which raises the multiplier precisely as the margin buffer shrinks.
And a fifth is reading a good run as evidence the leverage was appropriate. It is evidence the long losing run has not arrived yet, and on this series that run is 11 bars and already measured.
Related
Risk of ruin covers what a normal losing run costs once size is multiplied. Risk management covers the sizing rules that decide the multiple. And volatility covers the bar sizes every figure above is built from.
Leverage is sold as a way to trade a bigger position with less money, which is true and is not the point. The thing nobody says out loud is that it does not change your win rate, your average win, or anything else about whether the strategy works — it only changes how many ordinary bars it takes to end you.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.