A retail forex account is flat for about 48 hours a week. Prices stop updating some time on Friday evening and start again on Sunday evening, and in the interval an election is held, a central banker gives an unscheduled interview, a pipeline is attacked or a bank fails. When quoting resumes, the first tick does not have to be anywhere near Friday's last one.
That distance is the gap. It is not slippage in the normal sense, because nothing went wrong with execution. There simply was no price in between.
Why the stop does not protect you
A stop loss is a conditional order. It says: when the market trades at or through this level, turn my position into a market order. While the venue is closed there is no trading, so the condition never evaluates. At the reopen the condition is met instantly and the resulting market order fills at whatever the first executable price is.
If you were long EURUSD with a stop 40 pips below Friday's close and the pair reopens 120 pips lower, you exit around 120 pips down. Your stop was honoured. Your loss was three times what you planned. Nothing about that is a broker error, and no amount of stop discipline changes it, because the mechanism that makes stops work requires a live market.
Guaranteed stop products exist at some venues and charge a premium for exactly this scenario. They are worth understanding before assuming your ordinary stop behaves like one. Read our note on how stop orders behave in practice alongside this one.
Gap risk is also the main reason retail accounts can go negative. If the reopen prints far enough through your level, the fill can leave a balance below zero. Whether that is your problem or the firm's depends entirely on the rules of your jurisdiction and provider. See negative balance protection for how that works.
Which instruments gap hardest
Not every symbol behaves the same way over a weekend. What matters is how much genuinely tradable liquidity exists at the reopen and how exposed the underlying is to weekend headlines.
- Major FX pairs usually reopen close to the Friday level. The market is deep, and the Asian session absorbs small imbalances quickly. Quiet weekends often produce a gap of a few pips or none at all.
- Emerging market and exotic pairs gap far more often, because a single political story over the weekend can reprice the currency and the reopening book is thin.
- Indices and equity CFDs carry the gap risk of the cash market behind them. Earnings, index rebalances and policy statements all land outside the cash session.
- Crypto CFDs are the odd case. The underlying trades continuously, so the CFD reopens onto a price that already moved with no chance to react.
- Gold and oil respond to geopolitics faster than almost anything else, and geopolitics does not observe market hours.
Correlation makes this worse than it looks in a single position. If you hold three longs that all express the same view on the dollar, the weekend gap hits all three together. Our piece on pairs that move together explains why that book is really one position.
Sizing for the gap, not for the stop
The practical fix is to stop treating stop distance as your maximum loss on any position that will be open through the weekend. Two habits do most of the work.
First, decide before Friday whether the trade is a weekend trade at all. Many intraday setups have no reason to survive the close. If the thesis is measured in hours, closing on Friday costs a spread and removes a risk you were never being paid to take.
Second, when a position genuinely should be held, size it against a plausible gap rather than the stop. A workable rule of thumb is to assume the reopen can move against you by something in the range of a recent multi-day average range and check whether that outcome is survivable. That means knowing the instrument's normal range, which is what ATR and range measurement are for. If a two-day adverse move would breach your account's tolerance, the position is too big, whatever the stop says.
Reducing rather than closing is the middle path. Halving size into Friday's close keeps the exposure to the thesis and cuts the exposure to the reopen by the same fraction.
The Friday close itself is hostile
The last hour of the week is not a normal hour. Liquidity thins as desks flatten, spreads widen on most retail venues, and the price action becomes unrepresentative. Executing a considered entry into that window is usually a bad idea. If you must adjust, do it earlier in the New York session while the book is still deep.
The reopen has the mirror problem. Spreads at the Sunday open are frequently several times their weekday level for the first minutes, and a market order placed there pays for that. Pending orders sitting at the reopen deserve a second look on Friday, because a buy stop placed for Friday's context can trigger into a completely different Sunday market.
What firms do about it
Brokers carry the identical exposure. When a client's account goes below zero on a gap, the negative balance is the firm's loss unless it can be recovered. That is why margin requirements are commonly raised before the weekend on volatile symbols, why some venues force-close certain products ahead of the close, and why the triple swap charge for the weekend is booked mid-week rather than on Friday.
Prop firms take a different route and often write the rule directly into the challenge: no positions held over the weekend, or a reduced maximum exposure into Friday close. That is a risk decision about the firm's own book as much as a trading rule for the participant. Either way, read the rule before you plan a swing entry on a Thursday.
"People spend an hour choosing a stop level and then leave the position open through the only 48 hours where that level means nothing. Decide on Friday whether the trade deserves the weekend."
— Alex Onta, Executive Director, SINGUARD
Key Takeaways
- A stop cannot fill in a closed market. At the reopen it becomes a market order and fills at the first available price, however far away that is.
- Exotics, indices, crypto CFDs, gold and oil gap far more than major FX pairs, and correlated positions gap together as one exposure.
- Size weekend positions against a plausible adverse gap measured from recent ranges, not against the stop distance.
- Check pending orders before Friday close and expect wider spreads on both sides of the weekend break.
Frequently Asked Questions
Does a stop loss work over the weekend?
The order stays on the book, but it cannot fill while the market is closed. At the Sunday reopen the stop becomes executable at the first available price. If that price is beyond the stop level, the fill happens there, not at the level you set. A stop is an instruction to exit, never a promise about the exit price.
Do weekend gaps always get filled?
No. The idea that price always returns to Friday's close is a pattern people notice after the fact rather than a rule. Small gaps caused by thin liquidity often close early in the Asian session. Gaps caused by real news over the weekend can extend instead, because the information that created them is still being priced.
Why do brokers raise margin before the weekend?
Because the broker carries the same gap exposure the client does. Higher margin before Friday close reduces the size of positions that survive into a closed market, which limits how far accounts can fall below zero on a violent reopen. Some venues also widen spreads into the close and at the reopen while liquidity is thin.