Glossary · Prop Firms
Depth Of Market
Depth of Market (DOM) is a real-time display of the order book, showing multiple bid and ask price levels beyond the best bid and best ask. It reveals how much volume sits at each price, giving traders a read on available liquidity before placing an order.
Why it matters
DOM shows why a larger order can fill across several price levels instead of one, producing an average fill price worse than the top-of-book quote. Traders who read order flow through DOM can anticipate slippage and time entries or exits around visible liquidity rather than being surprised by it after the fact.
Live data
Example
Say a trader places a small market order on a futures contract. Because enough resting orders sit at the best ask, the order fills instantly at that single price. Now say another trader submits a much larger order in the same instrument. The best ask only has enough size to cover part of it, so the remainder consumes the next price level, and possibly the one after that. The result is a blended fill price worse than the quoted best ask, purely a function of order book depth at that moment.
Common misconception
Traders often see the effective spread widen as their lot size grows and assume something is wrong with the platform or their data feed. In reality, this reflects normal order book depth: fewer resting orders exist at each successive price level, so bigger orders naturally walk the book. Separately, many assume that Level 2 (DOM) data makes charts more "real time" or removes delay. It does not. Real-time pricing on charts comes from an active Level 1 subscription (best bid, best ask, last trade). Level 2 only adds the deeper order book behind those top-of-book prices, useful for order flow and execution timing, not for chart speed.
Related terms
See also
For firms where DOM and Level 2 data access (and any associated add-on fees) are most relevant, see the Futures Prop Firms category page.
Sources
Risk disclaimer: Trading carries a substantial risk of loss and is not suitable for everyone. Prop-firm evaluations charge fees and most traders do not pass. Nothing here is financial advice; figures can change, so verify current terms with the firm before purchasing.
Next step
See how firms actually apply this.
Compare current account sizes, rules, discounts and funding terms side by side.
