How to Read Market Depth and the Order Book

The market depth window (or order book) shows the pending buy and sell orders for a stock at different prices. Learning to read it gives a feel for short-term supply and demand.

What you see

Market depth typically shows the best five bid prices (buyers) on one side and five ask/offer prices (sellers) on the other, with the quantity queued at each. The gap between the best bid and best ask is the bid-ask spread.

What it tells you

• Liquidity — lots of quantity at many price levels means a liquid stock you can enter/exit easily.
• Spread — a tight spread means lower trading cost; a wide spread (common in penny stocks) means higher impact cost.
• Pressure — heavier quantity on the bid vs ask side hints at near-term buying/selling interest (though large orders can be withdrawn).

Use it with care

Depth is a snapshot that changes constantly, and visible orders can be spoofed or pulled, so don’t over-read it. It’s most useful for judging liquidity and placing sensible limit orders rather than predicting direction.

For active and intraday traders, checking depth before a trade helps avoid slippage. Education only, not a recommendation.