Order Book, Depth, and Queue

Order Book, Depth, and Queue explains order-book, depth, imbalance, and queue concepts used to understand visible market liquidity. Frame Order Book, Depth, and Queue around market structure: where prices form, how orders interact, and how liquidity or venue rules affect execution.

Use this branch when the question is what the visible book says about supply, demand, queue priority, and likely execution. This content is educational and does not recommend placing, canceling, or routing an order.

What This Branch Covers

Decision Lens

Order-book evidence is a snapshot, not a promise. Depth can change quickly, queue position can be lost after modification, and hidden or off-exchange liquidity may not appear in the visible book.

Move to Liquidity, Depth, and Transaction Costs when the issue is broader execution cost. Move to Quote Levels, Bid-Ask Terms, and Spreads when the issue is quote wording.

Evaluation Checklist

• Identify the venue, instrument, book type, timestamp, and whether the feed is real-time or delayed.
• Check depth at multiple price levels, not just the best bid and best offer.
• Confirm whether orders are displayed, hidden, reserve, auction-only, or conditional.
• Review venue rules for priority, modifications, cancellations, and odd-lot treatment.
• Use final execution reports to confirm whether book evidence translated into a fill.

Common Mistakes

• Treating book depth as stable during fast markets.
• Ignoring queue priority when estimating fill probability.
• Comparing books from different venues without understanding routing and fragmentation.
• Assuming displayed depth includes hidden or dealer liquidity.
• Reading an imbalance as a direction forecast without event and volume context.

For broader context, return to Market Quality and Microstructure.

In this section

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