This article is general information, not a recommendation to buy or sell anything. Academy articles are prepared by the ETTFOS team and other writers. They make no claim of expertise or accuracy, and they are not kept up to date after they are published.
Table of Contents
Most of the attention in trading goes to the idea: what to buy, what to sell, and when. Far less goes to a quieter question that often decides the outcome: how much.
Money management is the set of rules that answers it. It cannot make a bad idea good. It can stop one bad idea, or a run of them, from doing damage that cannot be repaired.
The arithmetic of losses
Losses and gains are not symmetrical. A loss shrinks the base that every later gain works from, so the gain needed to recover grows faster than the loss:
- A loss of 10% needs a gain of about 11% to get back to the start.
- A loss of 25% needs a gain of about 33%.
- A loss of 50% needs a gain of 100%.
- A loss of 75% needs a gain of 300%.
This is why small losses matter: keeping each loss small keeps the recovery within reach.
Start with money you can afford to lose
Regulators repeat this point for a reason. The SEC says day traders “should only risk money they can afford to lose.” FINRA says frequent intraday trading should never be funded with essential assets. For futures, the CFTC’s required risk disclosure warns that you may lose all the funds you deposit with your broker, “and you may incur losses beyond these amounts.”
Money management starts before the first trade, with how much money the trading account holds at all.
Sizing a position from its stop
A sizing rule works backwards. First it fixes the most a single trade may lose, as a share of the account. Then it measures the distance between the entry and the point where the trade is wrong. The position size is whatever makes the two fit.
Every trade then risks about the same amount, whatever the market. If the stop has to sit twice as far away, the position is half the size. A volatile market gets a smaller position, not a bigger hope.
The planned loss and the real one can still differ. A stop order becomes a market order when its price is reached, the CFTC explains, so a fast market or a gap can fill it beyond the stop. Sizing has to leave room for that.
Leverage works in both directions
Leverage lets a small deposit control a large position. The CFTC’s futures disclosure says it “can work against you as well as for you.”
The results show in the data. When the EU’s securities regulator, ESMA, restricted contracts for difference (CFDs) for retail clients in 2018, it said national regulators’ analyses showed that “74-89% of retail accounts typically lose money on their investments.” Its limits on retail leverage ran from 30:1 for major currency pairs down to 2:1 for cryptocurrencies.
When the UK’s FCA made its own restrictions permanent in 2019, it said: “We saw firms offering CFDs with increasingly higher leverage, resulting in high proportions of consumers losing money.”
Leverage does not change the quality of an idea. It changes how far the account moves when the idea is wrong.
Limits beyond a single trade
Sizing one trade well is not enough if several can go wrong together. Money management also sets limits for the whole account:
- Total exposure: how much of the account may be at risk across all open positions at once.
- Related positions: trades that tend to move together count as one larger position. FINRA says investments in the same industry, region or type of security “tend to be highly correlated.”
- Loss limits: a point, for a day or a week, at which trading stops and the plan is reviewed.
- Margin: on leveraged futures positions, the CFTC warns, a broker may call for substantial additional funds on short notice, and may close the position at a loss if they are not provided.
The takeaway
Position sizing is unglamorous, and it is where accounts are protected. The idea decides whether a trade can make money. The size decides whether a mistake can be survived.
A clear system treats both as rules, written down before the trade.
Your results will depend on your own decisions, your capital and market conditions, and you can lose money.
