Bid chart versus ask chart: why a sell stop triggers on the ask

[Amanhasnoname]

Most platforms draw candles from the bid price. That's a convention, and it hides something every scalper should know.

Orders for buying execute at the ask. Orders for selling execute at the bid. So a buy stop above the market triggers when the ask reaches the level, while a sell stop below triggers when the bid does. The chart only shows one of them.

For a long entry on a breakout, the chart might show a candle that never quite touches the buy stop, yet the order triggers because the ask is higher by the spread. For a short, the reverse can happen.

Putting the ask line on the chart is a simple way to see this. In MT4 and MT5 there is a setting to display it. With the ask visible, the gap between what the chart shows and what orders respond to becomes obvious.

The same logic applies to take-profits and stop-losses placed on short trades. A sell position closes at the ask, so a target set at a chart low can sit a full spread away from where the order actually triggers. Many unexplained near misses come from exactly this.

Does anyone keep the ask line on and use it for entries?