You place a limit order, see a trade at your price and wonder why your order remains open. One possible explanation is the queue: other eligible orders may have priority, and the available incoming quantity may not reach yours.
Nasdaq’s US equities overview describes its price/time model, including time priority among displayed limit orders at the same price and different treatment of non-displayed shares. This is a venue-specific explanation, not a universal rule for every exchange, auction or order type.
Follow a simplified queue
Imagine two displayed sell orders at 10.00 on the same book. Order A arrives first for 100 shares; order B arrives later for 80. If an eligible incoming buy order takes 120 shares under a simple price/time sequence, A can fill completely and B receive a 20-share partial fill.
Now add a displayed sell order at 9.99. Its better price can take priority over the 10.00 offers. This is why “I arrived earlier” is incomplete without asking at what price and under which matching rules.
Read the evidence your screen actually provides
A last-traded price does not show every order ahead of yours. It may also reflect a trade on another venue, while your broker’s routing and order conditions affect where your order can execute. A chart touching a level is therefore not a complete execution record.
Keep the order acknowledgement, time, venue or routing details where available, and any conditions you selected. If a fill surprises you, those records support a more precise question to your broker than a screenshot of the candle alone.
Changes can affect priority
Modifying an order may alter its queue position, depending on the venue and the kind of change. Check the applicable rules instead of assuming every edit preserves the original timestamp.
This example explains mechanics, not a trading recommendation. Price/time priority helps answer why two apparently identical limit prices can produce different outcomes. It does not guarantee execution, protect against price movement or tell you whether the investment itself is suitable.