Your order executed because the market did reach your price at the exchange — that trade just happened between the price samples shown on the chart, and faster than the market-depth (order book) snapshot updated on your screen. The chart and market depth are snapshots, not the complete tick-by-tick record, so they can miss the exact moment your order was matched.
Charts and market depth are snapshots
The exchange matches a huge number of trades every second, and neither view shows every one:
- The chart samples the price only a few times a second, so each candle is a snapshot — it may not show the exact high or low, or a brief move that matched your order.
- The market depth (order book) changes many times a second. What you saw was one snapshot; the buy/sell quantities shift — and your order can be matched — between refreshes.
Your order is matched against the actual trades at the exchange, tick by tick — so it can execute at a price the chart or depth never displayed on your screen.
What this means for you
- It's not an execution error — the market reached your price at the exchange, even if your screen didn't show it.
- To confirm the exact price and time, check your order and trade details rather than the chart or the depth snapshot.