Market depth

Market depth describes the volume of buy and sell orders available at each price level in the order book, beyond just the best bid and ask. It indicates how much can be traded before the price moves significantly. A deep market has substantial quantity resting near the current price, so large orders can be absorbed with little price movement; a shallow market has thin quantity, so even modest orders can shift the price.

Depth is often shown as a cumulative chart or a “depth of market” ladder. A common misconception is that displayed depth is fixed—orders can be added or cancelled at any moment, so depth changes continuously.