Queue position

Queue position is the place of a resting limit order within the line of orders at the same price and side, which under price-time priority determines how much size must trade at that level before the order is filled. It is set by arrival time, shortens as orders ahead are filled or cancelled, and is lost when the order is modified in a way the exchange treats as a new submission.

Senzoukria · Glossary · Updated September 2026

Price-time priority

On most futures exchanges, orders at the same price on the same side are filled in the order they arrived: first in, first out. An order joining a bid level that already holds 400 contracts must wait until those 400 have traded or been cancelled before it receives a fill. Its queue position is therefore the size ahead of it, not a fixed rank, and that size changes continuously. Some products use pro-rata or hybrid matching, where size rather than time decides the allocation; the exchange's matching rules for the specific contract are the reference.

  • Joining a level early gives priority; joining late puts the order behind everyone already there.
  • Cancellations ahead of you shorten the queue without any trade printing.
  • Increasing an order's size, or changing its price, usually sends it to the back of the queue; reducing size typically keeps priority. The exact rule is exchange-specific.

Why it matters on a large-tick book

On instruments where the spread sits at one tick almost all the time, such as ES with queues hundreds of contracts deep, most of the difficulty of passive execution is the queue rather than the price. A limit order at the best bid may never fill if price ticks away before the size ahead is consumed, and when it does fill, it is often because the level is about to be run through, so the fill arrives at the moment it is least welcome. The microstructure guide on this site makes the related point that the one-tick edge in queue imbalance disappears after queue position, latency and costs are accounted for.

Reading the queue on the DOM

  • The displayed size at your price is the total queue, ahead of and behind you; the DOM does not mark your own place in it.
  • Size ahead of you drops either through trades at that price (visible in the tape) or through cancellations (visible only as the number shrinking with no prints).
  • A level with a small displayed size is not necessarily a short queue: hidden slices of an iceberg can sit ahead of you.
  • Queue imbalance, the balance between resting size at the best bid and the best ask, is a snapshot of both queues and is distinct from any single order's position.

In Senzoukria

The DOM panel shows resting size per level per side, with Levels per side, a Large orders threshold and a depth view where faded levels were seen earlier in the session and are no longer in the live book. The Microstructure indicator's queue imbalance reading, computed from bid size and ask size at the best prices, describes which queue is heavier; it does not track any individual order's position. The comparison guide on this site describes the DOM's role as showing where the size sits at this instant and what is in front of an order. The application does not expose a per-order queue estimate; the size displayed at your price is the information available.

Common mistakes

  • Modifying an order's price or increasing its size to 'improve' it, and losing the priority already earned.
  • Assuming a fill at the best price is good news; on a deep queue, the fill often coincides with the level breaking.
  • Reading the total displayed size as size ahead of you when part of it arrived after your order.

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Frequently asked questions

Does cancelling and re-entering an order reset its queue position?
Yes. A cancelled order leaves the book, and a new order at the same price joins the back of the queue behind everyone currently displayed there. Reducing the size of an existing order usually preserves priority on price-time exchanges, while increasing it or changing the price does not; the contract's matching rules are the reference.
Is queue position the same as queue imbalance?
No. Queue position concerns one order and the size ahead of it at one price. Queue imbalance is a market-wide reading of resting size at the best bid versus the best ask, on a scale from minus one to plus one, used as a state read of the book. A heavy bid queue can coexist with a poor queue position for a late bid order.

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