Consistency rules: does your scalp distribution actually survive them?

[FXS London Scalper]

Many prop firms now have some form of consistency rule, typically that no single day may account for more than a set share of total profit, often 30–50%. For swing traders this rarely bites. For scalpers it depends on how results are distributed across days.

A quick test before you buy a challenge: export your daily P&L for the last three months and, for each month, divide your best day by the month's total profit. If that ratio is above the firm's limit, the month would have failed the rule.

A hypothetical profile shows the problem. A scalper has 20 trading days: 15 days between −0.5% and +0.5%, four days around +0.6%, and one news day of +2.5%. Total for the month: roughly +4.9%. The best day is about 51% of it, so a 40% rule fails, even though nothing about the trading was reckless. The profile that passes has more small positive days and no outlier, which isn't necessarily the more profitable one.

Two adjustments people use:

• A daily profit cap, for example 1.5 times the average winning day. When it's hit, the day ends.
• Slightly more activity on quiet days, but only with the best setups, never forced.

The cap hurts on the good days, but it shapes the distribution into what firms want.

Have you run your own history through a consistency rule before buying a challenge? What share did your best day come out at?