Weekend holding: what an overnight gap does to a funded account

Here is a rule that costs more accounts than almost any other and gets discussed the least: what happens to an open position between Friday's close and Monday's open. Many prop firms restrict or forbid holding across the weekend. The restriction is easy to read and easy to ignore, because a backtest rarely tells you it exists — and because the strategy that violates it often looks better than one that respects it.

This is about the gap: why overnight and weekend exposure is a different instrument from intraday exposure, and how to decide whether your edge can live inside the rule.

The gap is not a bigger candle

An overnight gap is a discontinuity, and discontinuity behaves differently from volatility in one specific way: it cannot be stopped out at a price.

Consider a long on an instrument that closes at $1.0000 on Friday. Over a weekend, news moves the open to $0.9800 on Sunday night. A stop at $0.9950 did not get you out at $0.9950. It got you out at the first available price, which is $0.9800 — 150 pips below your intended exit, on a single bar, with no chance to react.

That difference matters most in exactly the situation a funded account is most vulnerable: right after a good run. A trader who is up $6,000 on a $50,000 account with a $2,500 trailing floor has a floor that has climbed to $53,500. A weekend gap of 180 pips on a size that translates to 3% of the account is not a loss on the weekend. It is a hard breach at the open, before the first trade of the new week.

The gap did not exceed the drawdown. It exceeded the stops.

Why the rule exists at the firm

Two reasons, and it is worth understanding both because they shape how tightly firms enforce it:

1. Risk control across the book. A firm holding hundreds of accounts cannot hedge a shared directional exposure that every account carries into a weekend. Forbidding the hold removes a correlated tail risk from the entire portfolio at once.
2. Accountability for the gap. A gap is un-hedgeable and uncontrollable, which makes it the worst possible event for a firm that has to defend a maximum drawdown. It is the one loss that cannot be managed by skill, so the rule removes it by construction.

That is why the rule is usually a hard restriction with no fee-based workaround, unlike a daily-loss soft breach. Firms are not selling you a product you can pay to keep; they are removing an unmanageable risk from their book.

The two shapes of the rule

"Don't hold over the weekend" is written in at least three different ways, and they are not equivalent:

• No positions held through Friday's close. You must be flat before the close. The strictest form.
• No positions opened within a window before the close. You may hold a position opened earlier, but cannot add near the close. This is a hedging of the same risk, and it interacts with your entry timing rather than your holding policy.
• Instrument-specific. Some firms ban weekend holds on indices and FX but allow them on others, or vice versa. The restriction is in the instrument list, not the general rulebook.

Assume the strictest interpretation until you have read the firm's specific account-type rules. A general marketing page saying "swing trading allowed" frequently refers to the funded account, not the evaluation, or to a specific programme.

Is your edge actually a gap edge?

The question that decides everything: strip the overnight moves out of your backtest and look at what is left.

A quick way to do it — recompute the strategy using only the intraday path:

// Does the edge survive without the gap?
// Take the same signals, but close the position before the session ends
// and re-enter at the next open instead of holding through it.
function withoutGaps(trades) {
  return trades.map((t) => ({
    ...t,
    // Replace the overnight return with zero: the position is flat across the gap.
    pnl: t.pnlIntraday,
  }));
}

function withGaps(trades) {
  return trades.map((t) => ({ ...t, pnl: t.pnlIntraday + t.overnight }));
}

If the difference between withGaps and withoutGaps is most of the strategy's total return, the edge lives in the gap. That is not a flaw in the strategy — it is information. It means the strategy is incompatible with any firm that forbids the hold, and the correct response is to filter the firm list by that constraint before comparing anything else, not to try to trade it anyway.

If the difference is small, the strategy has an intraday core and the overnight component is noise. In that case the rule costs you little and you can ignore it.

The failure mode to guard against

The dangerous version of this is a trader who knows the rule, believes the overnight component is small, and is wrong — because the backtest understated it. Backtests frequently misprice overnight exposure in three ways:

• They fill at the close rather than the open, silently avoiding the gap.
• They assume the stop was honoured at its price on the gap bar.
• They use continuous synthetic bars that do not have gaps at all.

Each of those turns a real weekend risk into a modelled non-event. The fix is to reconstruct the strategy on actual session-boundary data, with the open price as the only fill available after a gap.

What to write down

Before buying any evaluation, three numbers:

1. The rule, in the firm's exact wording. Which instruments, which programme, which account type.
2. The overnight share of your edge. The withGaps minus withoutGaps difference, as a fraction of total P&L.
3. The gap risk in account currency. The worst historical weekend gap in your instrument, times your typical size — expressed in the drawdown's units, not pips.

If (2) is large, the rule is disqualifying for that firm and no sizing fixes it. If (3) is large relative to your remaining room, the same is true even for a small gap edge. The rule is not a formality you sign past; it is a constraint that eliminates some strategies and some firms, and the arithmetic that decides which is short and knowable in advance.

The firm-by-firm version of the rule — which programmes permit weekend holds, which ban them outright, and where the instruments differ — is in the weekend holding rules breakdown.