Overnight position rule (flat by close)
An overnight position rule requires positions to be closed by a stated time, usually before the session ends, and may forbid holding over the weekend. On prop firm accounts, a position still open at the cutoff can be liquidated by the firm or treated as a violation, whatever its profit.
Senzoukria · Glossary · Updated September 2026
What the rule says
The rule sets a cutoff, stated in a specific time zone, by which the account must be flat. Some firms apply it every trading day, others only before weekends and holidays. Some liquidate open positions automatically at the cutoff, possibly at an unfavorable price; others let the position run and record a breach. Brokers impose a related constraint through margin: intraday margin often applies only until a cutoff, after which the full exchange maintenance margin is required.
Why it exists
- Overnight and weekend holding exposes the account to gaps that stops cannot control.
- Thin overnight sessions make exits more expensive.
- Intraday margins that the account relies on usually do not apply to positions held through the close.
- For the firm, flat accounts at the close simplify risk control and daily settlement.
Planning for the cutoff
Know the cutoff in your local time, including daylight saving changes on both sides. Stop opening new trades early enough that a normal holding time ends before the cutoff, and close manually rather than relying on the firm's liquidation. For strategies tested on data that includes overnight holds, remove or truncate those trades at the cutoff and recompute the results.
In Senzoukria
The prop firm rule engine does not see the time of each trade, so a no-overnight restriction is listed as not simulated in the presets that include one. For respecting the rule in practice, the autopilot accepts an optional session window in local time and, by default, flattens its position when the window closes. Flatten all cancels every working order and closes every position of the account from one control, and the prop engine's trading day switches at 17:00 Chicago time, the CME session change, so daily limits and trading-day counts follow the exchange day rather than midnight.
Related
In the same section
- Overtrading
- Overnight inventory
- P-shaped profile
- Overnight high / low
- p-value
- Overfitting
- Paper trading
- Outcome bias
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Frequently asked questions
- Is holding through the CME daily break the same as holding overnight?
- For most prop firm rules, what matters is the firm's stated cutoff time, which is often shortly before the daily session ends. A position open through the daily break is usually considered held overnight. The account terms define it.
- What if the firm liquidates my position at the cutoff?
- The liquidation is a market order at the cutoff, filled at whatever price is available. The result counts toward the account's drawdown and daily loss like any other trade, so closing yourself a few minutes earlier is usually preferable.