Prop firms let you trade their capital in exchange for proving, in an evaluation, that you can control risk. Most traders who fail don't fail for lack of profit but for breaking a rule: the daily loss limit, the max drawdown or the consistency rule. This guide explains how each rule works, with worked examples, and how to organise your trading so you don't break them.
Every firm defines its rules its own way and changes them over time. The examples in this guide are illustrative: always read the exact terms of your account before trading.
How a prop firm evaluation works
The usual model has three stages:
- Evaluation (challenge): you pay a fee and trade an account, usually simulated, with a profit target and risk rules. Some firms have a single phase and others two.
- Funded account: if you pass, you get a funded account, sometimes after paying an activation fee. The risk rules still apply.
- Payouts: you keep a percentage of the profits you generate, according to the firm's schedule and conditions.
Breaking a risk rule, at any stage, usually means losing the account. So the real goal isn't to make a lot, but to make money without ever touching the limits.
Max daily loss
The most you can lose in a single day. It's usually set as a fixed amount or a percentage of the starting balance. What matters is knowing how your firm measures it:
- Intraday: if at any point in the day your losses reach the limit, the rule is broken, even if you recover later.
- End of day: only the result the session closes with counts.
On top of that, some firms count only closed trades while others include floating losses on open positions.
Example. A $50,000 account with a $1,100 daily limit. You start the day at $51,000, so that day you can't go below $49,900. At 11:00 you're down $1,150 and by the close you've recovered to −$300. Measured intraday, you broke the rule at 11:00. Measured at the close, the day counts as −$300 and the account is still alive.
Also check what time the trading day resets for your firm, which isn't necessarily your midnight.
Static max drawdown
Max drawdown sets a floor your account can never fall below. In the static version, that floor is fixed:
Floor = starting balance − max drawdown
With $50,000 and a $2,000 max drawdown, the floor is always $48,000. If you make $3,000 and then lose $4,500, the account sits at $48,500 and is still alive. It's the most forgiving version: every dollar you make moves you further from the floor.
Trailing drawdown
With a trailing drawdown the floor rises when your account sets new highs, and never comes down. Many firms stop trailing once the floor reaches the starting balance. This is how a $50,000 account with a $2,000 trailing drawdown, calculated at each day's close, evolves:
| Day | Closing balance | Highest balance | Floor | Room left |
|---|---|---|---|---|
| Start | $50,000 | $50,000 | $48,000 | $2,000 |
| 1 | $50,800 | $50,800 | $48,800 | $2,000 |
| 2 | $51,200 | $51,200 | $49,200 | $2,000 |
| 3 | $50,600 | $51,200 | $49,200 | $1,400 |
| 4 | $52,300 | $52,300 | $50,000 (locked) | $2,300 |
| 5 | $51,000 | $52,300 | $50,000 | $1,000 |
The treacherous part of a trailing drawdown is that your profits don't give you a cushion: on day 3 the account is $600 above its starting balance, yet you only have $1,400 of room, less than when you started. And if the firm trails the intraday high (including open profit), letting a winner turn around also raises the floor without you banking anything.
Profit target
In the evaluation you need to reach a set profit, for example 6% or 8% of the starting balance. Funded accounts usually have no target, but some firms require you to build a buffer before the first payout.
The classic mistake is treating the target as a deadline. With risk sized properly, the target arrives as a consequence of trading your plan; if you chase it by sizing up, the drawdown will most likely arrive first.
Minimum trading days
Many evaluations require a minimum number of trading days, for example five, before you pass, even if you've already hit the target. A day usually counts when you close at least one trade. If you reach the target early, there's no need to risk more: trading small size on the remaining days is enough.
The consistency rule
The consistency rule caps how much of your profit can come from a single day. The most common version:
Best day ÷ total profit ≤ limit (for example, 40%)
Example. You've made $3,000 in total, and your best day contributed $1,500: 50%. With a 40% limit, you don't comply yet. To comply without losing that day, your total profit needs to reach 1,500 ÷ 0.40 = $3,750, meaning $750 more spread across other days.
The rule aims to show that your result is repeatable rather than the product of one lucky trade. It's the same idea as the best-day share used as a consistency metric.
Other common rules
- News: bans on opening or holding positions around high-impact releases.
- Overnight and weekends: positions must be closed before a set time or before the weekend.
- Max size: a cap on contracts or lots, sometimes scaled with accumulated profit.
- Prohibited strategies: latency arbitrage, hedging across accounts or copying third-party trades.
- Inactivity: losing the account if too many days pass without trading.
How to size risk so you don't break the rules
The most reliable way to respect the limits is to choose your risk per trade with losing streaks in mind. For the account in the examples, with a $1,100 daily loss limit and a $2,000 drawdown:
| Risk per trade | Losses in a row you can take without hitting the daily limit | Losses in a row you can take without hitting the drawdown |
|---|---|---|
| $100 | 10 | 19 |
| $200 | 5 | 9 |
| $300 | 3 | 6 |
| $500 | 2 | 3 |
With a 50% win rate, a streak of about six losses in a row over a hundred trades is perfectly normal. Risking $500 per trade, six losses are $3,000: more than the whole drawdown. Risking $200 they're $1,200 and the account survives, although if they came on the same day they would break the daily limit; hence the importance of also capping the number of trades per day. That's why your personal limits should be stricter than the firm's: for example, stopping for the day after losing half the daily limit.
These calculations are arithmetic, not investment advice: the right risk depends on your system, your account and your firm's exact rules.
Costs and your real return
Evaluation fees, resets and activations are a real expense. To know whether prop firms are actually making you money, compare what you've paid with what you've been paid:
Return = (payouts + refunds − fees − resets − activations) ÷ total costs
If you've paid for three $150 evaluations, a $100 activation and an $80 reset ($630 in total) and withdrawn $1,200, your net result is +$570 and your return on what you've put in is about 90%. Without keeping this tally, it's easy to believe you're ahead while every new evaluation eats your payouts.
How to track the rules every day
- Before the open, note your room to the daily loss limit and to the drawdown.
- Set your risk per trade so that a normal streak doesn't touch either.
- Set personal limits stricter than the firm's and respect them as if they were official.
- At the close, update your balance, highest balance, floor and consistency.
- Record every fee and every payout to know your real return.
NactionX does this tracking for you on every evaluation or funded account: daily loss measured intraday or at the close, static or trailing drawdown, profit target, minimum days and consistency, plus fees and payouts. It calculates from the closed trades you log, so for rules that include floating losses your platform remains the real-time reference. To work out your personal limits, see the guide on how to write a trading plan.