Why a stop-loss on a short fills at the ask and still surprises people
Posted: Sat Oct 31, 2026 10:52 pm
A sell position displays a profit or loss based on the bid, since that's where it can be closed. The stop-loss on that same short triggers on the ask, since closing a short means buying. Many traders know this in theory. Fewer feel it in practice until a stop gets hit and the chart "never touched" the level.
On a bid-based chart, price might have peaked a pip below the stop. The ask, which is bid plus spread, reached it. During quiet hours the difference is a fraction of a pip. During rollover or news, the spread can be five or ten pips wide, and a stop that looked safe on the chart triggers on a spread spike.
The reverse matters for longs: stops trigger on the bid, so a spread spike can take out a long stop even when the mid price barely moved.
Switching the platform to display the ask line, or using a chart based on the ask, turns many of these "inexplicable stop-outs" into obvious ones.
A concrete example: a short is opened at 1.0850 with a stop at 1.0860. The bid chart tops out at 1.0858 and turns around. On that chart, the stop was never touched. The ask, with a 2.5 pip spread at that instant, reached 1.0860.5 and closed the trade. The platform's history shows the exit at the stop level, and the chart seems to disagree.
The disagreement is the spread, and it is largest when it matters least to remember. Adding an ask line to the chart takes one click in most platforms. After a week of seeing both lines, the "phantom" stop-outs become predictable.
Take-profit orders on shorts work the other way around. They trigger on the ask touching the target, which means price needs to go a little further on the bid chart to fill. That is the quiet cost of the spread on the profit side.
Is a second line for the ask worth the clutter on a bid-based chart?
On a bid-based chart, price might have peaked a pip below the stop. The ask, which is bid plus spread, reached it. During quiet hours the difference is a fraction of a pip. During rollover or news, the spread can be five or ten pips wide, and a stop that looked safe on the chart triggers on a spread spike.
The reverse matters for longs: stops trigger on the bid, so a spread spike can take out a long stop even when the mid price barely moved.
Switching the platform to display the ask line, or using a chart based on the ask, turns many of these "inexplicable stop-outs" into obvious ones.
A concrete example: a short is opened at 1.0850 with a stop at 1.0860. The bid chart tops out at 1.0858 and turns around. On that chart, the stop was never touched. The ask, with a 2.5 pip spread at that instant, reached 1.0860.5 and closed the trade. The platform's history shows the exit at the stop level, and the chart seems to disagree.
The disagreement is the spread, and it is largest when it matters least to remember. Adding an ask line to the chart takes one click in most platforms. After a week of seeing both lines, the "phantom" stop-outs become predictable.
Take-profit orders on shorts work the other way around. They trigger on the ask touching the target, which means price needs to go a little further on the bid chart to fill. That is the quiet cost of the spread on the profit side.
Is a second line for the ask worth the clutter on a bid-based chart?