Explainer
Consistency rule explained
A consistency rule limits how much of your total result a single day or trade may make up, so one large day cannot carry an account to its target.
Updated
The short version
A consistency rule looks at how the result is spread. It takes your largest day, or your largest trade, and compares it with the total. If that one day makes up more of the total than the rule allows, the account does not meet the rule, whatever the total is.
The rule does not care how large the result is. It cares how it was built. Programs set their own thresholds and their own wording, so check the rulebook for yours.
- Consistency rule
- A rule limiting how much of the total result one day or trade may make up.
- Largest day
- The trading day with the highest result in the period the rule looks at.
- Total result
- The sum of the results over that period.
- Spread
- How the result is divided across days or trades.
How it is measured
In outline, the rule is a ratio. Take the result of the largest day and divide it by the total result. Compare the answer with the limit the program sets.
Programs differ on the details. Some look at days and some at trades. Some count only the evaluation period. Some apply the rule only when you ask to be paid or moved on. The rulebook tells you which.
A consistency rule is a ratio. It looks at how your result is spread across days, not how big the result is.
Why a program uses one
A firm wants to see a trading approach that repeats, not one lucky day. A rule on the spread of the result is a simple way to check that a single large trade did not do all of the work.
You do not need to agree with the reason to plan around the rule. It is part of the environment your strategy trades in.
Early in an attempt, one day is most of the total
The ratio has a plain arithmetic feature. When the total is small, one day is a large share of it. On the first day with a result, that day is all of the total.
So the rule behaves differently at different stages of an attempt. A spread that looks uneven early can even out as more days arrive, and it can also tip the other way. Read the rule for when it is checked.
Seeing it in a backtest
Every trade in a run has a date, so you can group the trades by trading day and add up each day in R. Then divide the largest day by the total, the same way the rule does.
Count the trades behind the numbers as well. A strategy with few trades can have a large share in one day simply because there are few days with trades. A strategy with many trades spreads over more days. The trade count in the findings shows which case you are in.
Our service holds back about 30% of months, spread across every year. Reading the spread by year, and across the months that were held back, shows whether the result came from one stretch of the history.
What a rule like this changes in your plan
If your rules take profits in a few large moves, the largest day can be most of the total. If they take many small ones, it usually is not. Neither says anything about the strategy’s worth. It is a fact about how the result is spread, and the rule asks about exactly that.
You can test a change, such as a cap on the number of trades per day, as a new version and read the spread again. Each version is $19.
Questions and answers
What is a consistency rule in prop trading?
It is a rule limiting how much of the total result one day or trade may make up, so the result is spread across days.
How is a consistency rule calculated?
In outline, the result of the largest day divided by the total result, compared with the limit the program sets. The exact method is in the program’s rulebook.
Does every prop firm have a consistency rule?
No. Some programs have one and some do not, and the threshold and wording differ.
Can a backtest show how consistent a strategy is?
It can show how results were spread across days and years, by grouping dated trades. It cannot say whether a program’s rule would be met in a future attempt.