Setting a Daily or Weekly Loss Limit

A circuit breaker for the trading day

A daily or weekly loss limit is a point, fixed in advance, at which you stop trading for that period regardless of what the market is doing or how strongly you feel about the next setup. Per-trade risk protects you from any single bad trade. It does nothing to protect you from a sequence of decisions made in the state that follows three losses in a morning, which is the state most responsible for genuinely damaging days.

The rule exists because the failure it prevents is a spiral rather than an event. One loss leads to a hurried attempt to recover it, which leads to another loss at larger size, which raises the urgency again. Each step feels locally reasonable. The sequence is what destroys accounts, and the only reliable intervention is one that was decided before the first loss.

How to set the numbers

Those figures are a starting point rather than a prescription. What matters more is the relationship between them: the daily limit should be roughly three times your per-trade risk, so that a normal bad day costs about three losing trades and not ten, and the weekly limit should allow two bad days without ending the week.

If you risk 1% per trade, a 3% daily limit means three full losses ends the session. If you risk 0.5%, the same 3% allows six, which may be too many to sit through calmly. Set the limit in trades as well as in percent, and let whichever arrives first apply.

The rules that make it work

• Set it while calm, before the session. A limit chosen mid-drawdown will be chosen to accommodate the trade you want to take.
• Reaching it means stopping, not trading smaller. "I will just size down" is the spiral with better manners. The platform gets closed.
• Never adjust it mid-session. The only acceptable time to change the number is between periods, with a written reason.
• Count floating losses. A limit measured on closed trades only can be evaded by holding a large loser open, which is the exact behaviour the rule should prevent.
• Apply it to good days too. Many traders add a profit-based stop for the day, because the trades taken after an unusually large win are often the ones that give it back.

The weekly limit deserves its own thought. A daily rule alone lets a poor week run to five consecutive bad days, which at 3% a day is a 14% drawdown reached entirely within the rules. The weekly figure is what stops a run of individually acceptable days from adding up to an unacceptable month, and it is the limit most traders leave out.