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TL;DR

The list of all outstanding limit orders in a market, organized by price level. The bid side shows buy orders (descending price), and the ask side shows sell orders (ascending price).

By Valenke Exam Prep Team·Last updated 2026-06-03

Order Book

The list of all outstanding limit orders in a market, organized by price level. The bid side shows buy orders (descending price), and the ask side shows sell orders (ascending price).

Why it matters for interviews

The order book is the core data structure of electronic markets. Understanding book dynamics (order flow, queue position, market impact) is fundamental for algorithmic trading and market-making strategies.

Definition and Mathematical Foundation

The list of all outstanding limit orders in a market, organized by price level. The bid side shows buy orders (descending price), and the ask side shows sell orders (ascending price).

Application in Quantitative Finance

The order book is the core data structure of electronic markets. Understanding book dynamics (order flow, queue position, market impact) is fundamental for algorithmic trading and market-making strategies.

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Frequently Asked Questions

What is the difference between market orders and limit orders?
Market orders execute immediately at the best available price (take liquidity). Limit orders specify a price and wait in the book (provide liquidity). The tradeoff is certainty of execution vs. price improvement.
What is order book depth?
The total quantity available at each price level. Deep books can absorb large orders without significant price impact. Thin books have high market impact, making execution more costly.
What is the bid-ask bounce?
The apparent negative autocorrelation in transaction prices caused by trades alternating between bid and ask. It inflates measured volatility and must be accounted for in microstructure analysis.