Why stop-loss fills are worse than the bid
Posted: Sat Oct 31, 2026 9:21 pm
When a stop triggers, the order becomes a market order. Most traders expect the fill at the stop price, or within a pip of it. Often it's worse than the current bid, and that bothers people.
There are several reasons. First, the stop triggers on the ask for a short and the bid for a long, which is correct and expected. Second, the market order travels to the broker and then to a liquidity provider, taking time. Third, in a fast market, the provider's last look can reject the first attempt and fill a second, at a worse price.
Some brokers add a small buffer to stops, giving the server permission to fill at a worse price. Others apply different slippage rules to stops than to entries, often less favorable to the client.
A comparison helps. For a hundred stop-outs, measure the difference between the stop level and the fill price. Do the same for a hundred market entries. If stops are systematically worse, the platform treats them differently.
The size of the gap may be 0.2 pips in quiet markets and 3 in fast ones. A strategy that assumes zero slippage on stops needs to be checked against this number.
Another detail: the spread at the moment of the stop matters. A stop on a short position triggers on the ask. If the spread has widened from 0.4 to 1.5 pips because of a brief liquidity thinning, the stop triggers 1.1 pips earlier than the chart showed. The chart is drawn from bids, so the visible candle didn't even reach the stop level.
Those stop-outs feel like manipulation and look bad on a bid-only chart. Overlaying the ask line, or switching the chart to show ask prices for shorts, explains most of them and shows which trades were really a matter of widening spread rather than price movement.
What's the average stop slippage on the account used here compared with entry slippage?
There are several reasons. First, the stop triggers on the ask for a short and the bid for a long, which is correct and expected. Second, the market order travels to the broker and then to a liquidity provider, taking time. Third, in a fast market, the provider's last look can reject the first attempt and fill a second, at a worse price.
Some brokers add a small buffer to stops, giving the server permission to fill at a worse price. Others apply different slippage rules to stops than to entries, often less favorable to the client.
A comparison helps. For a hundred stop-outs, measure the difference between the stop level and the fill price. Do the same for a hundred market entries. If stops are systematically worse, the platform treats them differently.
The size of the gap may be 0.2 pips in quiet markets and 3 in fast ones. A strategy that assumes zero slippage on stops needs to be checked against this number.
Another detail: the spread at the moment of the stop matters. A stop on a short position triggers on the ask. If the spread has widened from 0.4 to 1.5 pips because of a brief liquidity thinning, the stop triggers 1.1 pips earlier than the chart showed. The chart is drawn from bids, so the visible candle didn't even reach the stop level.
Those stop-outs feel like manipulation and look bad on a bid-only chart. Overlaying the ask line, or switching the chart to show ask prices for shorts, explains most of them and shows which trades were really a matter of widening spread rather than price movement.
What's the average stop slippage on the account used here compared with entry slippage?