Depth of market

What is Depth of market in forex and CFD trading

Depth of Market (DOM), also known as Level 2 or market depth, is a display showing the real-time volume of buy and sell orders for a financial instrument in forex and CFD trading at various price levels away from the current best bid and offer (BBO). The Depth of Market matters for real trading decisions because it provides critical insight into the liquidity and potential support/resistance levels near the current price, allowing large-volume traders to anticipate execution quality and slippage before placing an order. A trader can verify or measure the Depth of Market by activating the DOM window or Level 2 data on their trading platform, typically available through platforms like MT5 or TraderEvolution, and observing the displayed volume in lots or units associated with each sequential price level. For more trading terms, check our forex glossary.

Key facts about Depth of market

• Data Source: Depth of Market data is only available from brokers operating a true Electronic Communication Network (ECN) or Direct Market Access (DMA) model, aggregating quotes from multiple liquidity providers.
• Format: It is typically presented as a vertical stack of limit orders, displaying the price level, the aggregate volume of resting Buy Limit orders (Bids), and the aggregate volume of resting Sell Limit orders (Asks).
• Top Level: The price level closest to the market, known as the Level 1 quote, shows the Best Bid and Offer (BBO), representing the tightest available spread.
• Liquidity Measurement: The total volume available at each price level measures the liquidity of the instrument, determining how much a large order would shift the price (market impact).
• Predictive Value: Traders use DOM to identify liquidity imbalances, where a large volume of orders on one side may signal near-term directional bias or indicate areas of potential exhaustion.
• Volume Unit: Volume is typically displayed in standard lot equivalents or a specific number of units, depending on the platform configuration.
• DOM Limitations: The displayed DOM is often proprietary to the broker’s specific liquidity pool, not the full, global market depth.

How Depth of market works in forex and CFD trading

Depth of Market provides a snapshot of the order book, which represents the supply and demand currently posted as pending limit orders in the system.

The process of DOM utilization follows these steps:

1. Liquidity Aggregation: The ECN system continuously collects and aggregates all limit orders placed by various liquidity providers and clients across the network.
2. Price Stacking: These aggregated volumes are organized by price level, showing how much volume is available to buy (Bid volume) and sell (Ask volume) at prices incrementally away from the current market price.
3. Spread Visualization: The gap between the highest Bid price and the lowest Ask price forms the spread, which is the narrowest point on the DOM display.
4. Market Execution Simulation: A trader with a large volume order (e.g., 50 standard lots) can visually trace how their order would be filled by looking at the sequential price levels necessary to absorb the entire 50-lot volume.
5. Impact Estimation: The cumulative volume needed to fill the order determines the potential execution price and the subsequent slippage, also known as market impact.
6. Real-Time Update: The DOM is continuously updated as limit orders are placed, modified, canceled, or filled by incoming market orders.

Example of Depth of market with a real trade

This example demonstrates how a trader uses DOM to estimate the slippage cost before placing a large Market order.

Scenario: A trader intends to buy 5 standard lots of EUR/USD using a Market Order.

• Current Best Bid: 1.10000 (0 lots offered)
• Current Best Ask: 1.10002 (3 lots offered)
• Next Ask Level: 1.10003 (5 lots offered)
• Subsequent Ask Level: 1.10004 (10 lots offered)

DOM-Based Execution Calculation:

• Order Size: 5 standard lots (500,000 units).
• Fill at 1.10002: The first 3 lots of the order will be filled at the best Ask price of 1.10002.
• Remaining Volume: 5 – 3 = 2 lots remaining to be filled.
• Fill at 1.10003: The remaining 2 lots will be filled at the next price level, 1.10003, consuming 2 of the 5 lots available at that price.

Average Execution Price: Average Price = ((3 × 1.10002) + (2 × 1.10003)) / 5 Average Price = (3.30006 + 2.20006) / 5 = 5.50012 / 5 = 1.100024

Result: 5 standard lots bought at an average price of 1.100024. The execution involves 0.4 pips of slippage (market impact) from the initial best Ask of 1.10002.

How Depth of market affects your cost and risk

The Depth of Market provides transparency that directly allows traders to assess the Market Impact Cost of their execution, which is the effective slippage beyond the spread, thereby influencing execution risk management.

Depth of market compared with related concepts

Depth of market vs Spread

Depth of Market is a display of volume at price levels away from the current quote, indicating the cost of execution for larger trades through potential slippage. Spread is the difference between the best Bid and best Ask price (the BBO), representing the immediate, fixed cost of a small-volume trade. DOM shows the liquidity behind the spread, while the Spread is just the top layer of the DOM.

Depth of market vs Tick Data

Depth of Market is a static view of pending volume at various price levels, providing insight into market structure and immediate liquidity. Tick Data is a time-series record of executed transactions (price and volume), providing historical information on past price movements and realized volumes. DOM is predictive and structural; Tick Data is historical and reactive.

How Afterprime handles Depth of market

Afterprime provides genuine Level 2 Depth of Market data to clients through MT5 and TraderEvolution platforms, where supported. This allows traders to see the aggregated limit order volume from Afterprime’s multiple liquidity providers. The data reflects the real market structure, which is crucial for high-frequency and volume traders managing market impact risk and seeking tight execution with speeds under 50 milliseconds.

Broker differences in Depth of market across the industry

The type of execution model dictates whether a broker can provide meaningful Depth of Market data to its clients.

How to verify Depth of market on your trading platform

Verifying the Depth of Market requires using a platform, such as MT5 or TraderEvolution, that is designed to display order book data.

1. Launch Trading Terminal: Open the MT5 or TraderEvolution platform.
2. Select Instrument: Click on a currency pair, such as EUR/USD, in the Market Watch or Symbols list.
3. Access the DOM: In MT5, navigate to View > Depth of Market, or press the appropriate hotkey. In TraderEvolution, locate the “Market Depth” or “DOM” panel.
4. View Price Levels: Observe the list of prices in the center, with the Bid (Buy) volume stacked on one side and the Ask (Sell) volume stacked on the other side.
5. Check Volume Scale: Confirm that the volume displayed is in real units or lots, typically 100,000 units per standard lot.
6. Place Order within DOM: Use the one-click trading feature within the DOM panel to place an order directly at a chosen price level, where supported.
7. Sanity check: A true Depth of Market display must show volumes attached to prices incrementally away from the BBO; if only the BBO is shown, it is not a Level 2 DOM.