Dear Users,
For BingX CFD trading, the platform provides an order book (OB) as a reference for market liquidity. The order book shown on this trading page differs from the order book of a typical matching exchange. Since CFDs are a TradFi (traditional finance) product, their liquidity sources and operating mechanisms are unique. The platform therefore displays reference liquidity rather than a traditional matching-based order book. This article explains how reference liquidity works, defines the mid price and how it's calculated, and covers what to keep in mind when trading.
1) Why does the platform show reference liquidity?
You may notice that the order book on the CFD trading page looks similar to the order book in spot or futures trading, but the underlying logic is completely different. Here's why:
1. Different liquidity sources
The CFD TradFi business aggregates quotes from multiple liquidity providers (LPs). The system calculates potential quote depth for reference based on the quotes and available liquidity provided by each LP.
2. Non-matching mechanism
Since actual execution ultimately depends on real liquidity from the LP side, this order book doesn't perform order matching. Instead, it shows the current market's approximate bid and ask price distribution as an indicative reference.
3. Symmetrical bid and ask sides are normal
In reference liquidity, the price levels on the ask side and the bid side show a symmetrical structure. This is normal. At the same time, the displayed executable size is very close to the actual tradable volume, giving it strong reference value.
2) Order book structure
In CFD trading, the middle of the order book (OB) usually shows the mid price, which helps you quickly see the midpoint between the current bid and ask prices. The order book lists all unfilled orders in the current market, usually divided into two sides:
| Area | Name | Meaning |
| Upper | Ask | The prices and sizes at which sellers are willing to sell, listed from lowest to highest |
| Lower | Bid | The prices and sizes at which buyers are willing to buy, listed from highest to lowest |
| Middle | Mid Price | The arithmetic average of the best bid price and the best ask price |
Order book structure illustration:
| Level | Price (USD) | Size (XAU) |
| Ask 5 | 65,050 | 0.5 |
| Ask 4 | 65,040 | 1.2 |
| Ask 3 | 65,035 | 0.8 |
| Ask 2 | 65,025 | 2 |
| Ask 1 | 65,020 | 1.5 |
| Mid Price | 65,010 | |
| Bid 1 | 65,000 | 1.8 |
| Bid 2 | 64,990 | 2.5 |
| Bid 3 | 64,985 | 0.6 |
| Bid 4 | 64,970 | 1.1 |
| Bid 5 | 64,960 | 3 |
In the diagram above, the mid price of 65,010 is the midpoint between the best bid price (65,000) and the best ask price (65,020).
3) What is the mid price?
1. Difference from regular trading
In regular trading (such as spot and Standard Futures), the middle of the order book usually shows the last traded price (LTP), which is the price of the most recent actual trade.
But for CFD reference liquidity, the middle doesn't show the last traded price. Instead, it shows the mid price, a reference value calculated from the best ask price and the best bid price.
| Comparison item | Regular trading | Reference liquidity |
| What's shown in the middle | Last traded price (LTP) | Mid Price |
| Definition | The price of the most recent trade | (Ask 1 + Bid 1) ÷ 2 |
| Nature | Actual historical trade | Real-time value calculated from current quotes |
2. Calculation formula
Mid price = (Bid 1 + Ask 1) ÷ 2
Example 1: XAUUSD CFD contract
| Item | Price |
| Ask 1 | 65,020 USD |
| Bid 1 | 65,000 USD |
| Mid Price | (65,020 + 65,000) ÷ 2 = 65,010 USD |
| Spread | 20 USD |
Example 2: XAGUSD CFD contract
| Item | Price |
| Ask 1 | 3,401.5 USD |
| Bid 1 | 3,400.5 USD |
| Mid Price | (3,401.5 + 3,400.5) ÷ 2 = 3,401.0 USD |
| Spread | 1.0 USD |
4) Uses and significance of the mid price
In CFD trading, the mid price is mainly used in the following scenarios:
1. Quickly assess market price levels
The mid price is the midpoint between the bid and ask quotes, letting users quickly gauge the current CFD contract's general market level without comparing every price in the order book.
2. Measure the spread
Spread = Ask 1 − Bid 1. By observing the distance between the mid price and Bid 1/Ask 1, you can indirectly assess the current liquidity conditions:
| Spread condition | Meaning |
| Narrower spread | Sufficient liquidity, an active market, and lower trading costs |
| Wider spread | Weak liquidity, a quiet market, and higher trading costs |
3. Reference benchmark for floating PnL
In some scenarios, the platform may use the mid price or mark price as the basis for displaying floating PnL on positions, helping users assess their position status more objectively.
4. Support trading decisions
Users can use the mid price to judge whether a limit order's placement is reasonable. For example, if your buy limit price is far below the current mid price, the order is less likely to fill. If your sell limit price is far above the current mid price, it is also less likely to fill.
5) Important notes
1. The mid price is for reference only and does not represent the actual filled price
The mid price is a calculated reference value, not an actual order price that exists in the market. You cannot fill any order directly at the mid price.
2. The actual filled price is based on the best price in the order book
| Trade Direction | Actual filled price based on | Description |
| Buy (open long / close short) | Ask 1 (best ask price) | You buy from the seller offering the lowest ask price |
| Sell (open short / close long) | Bid 1 (best bid price) | You sell to the buyer at the highest bid price |
3. The platform does not support placing or matching orders at the mid price
Does not support submitting market orders or limit orders at the mid price.
Does not offer an automatic matching mechanism based on the mid price.
All orders are matched in the order book using actual order prices (Bid/Ask).
4. The mid price may differ from the mark price
The mark price is typically calculated from multiple data sources and is used to determine liquidation, while the mid price is calculated only from the current best bid and best ask in the order book. The two may differ.
5. Availability of reference liquidity
This currently applies only to certain TradFi trading pairs. If a pair does not support reference liquidity, this announcement entry link will not be displayed on the pair's trading page.
During market closures, reference liquidity will be temporarily unavailable and will automatically resume once the market reopens. This is normal.
6. Scheduled MT5 system restarts
To ensure stable system operation and the best trading experience, the MT5 trading server will undergo scheduled restart maintenance after market close every Friday. This process takes some time.
During the restart, trading features (including placing orders, closing positions, querying, etc.) will be temporarily unavailable, and ongoing trades may also be affected or interrupted. Service will automatically return to normal once maintenance is complete.
We recommend planning your trades in advance and avoiding urgent operations around market close every Friday to prevent inconvenience. This is part of our routine system maintenance and is completely normal.
5) Diagram: Mid price vs. Actual filled price
The following scenario illustrates the relationship between the mid price and the actual filled price:
Scenario: You want to buy an XAUUSD CFD contract at market price.
| Trade Direction | Actual filled price | Mid Price | Difference |
| Buy (long) | 65,020 (Ask 1) | 65,010 | +10 USD |
| Sell (short) | 65,000 (Bid 1) | 65,010 | −10 USD |
- When you buy, the filled price is 65,020 (Ask 1), not 65,010.
- When you sell, the filled price is 65,000 (Bid 1), not 65,010.
- The mid price of 65,010 never becomes the filled price for either side.
6) FAQ
Q1: Can I fill an order at the mid price?
A: No. The mid price is a reference value for display purposes only. All CFD orders on the platform are matched using the actual order prices (Bid/Ask) in the order book, and filling orders at the mid price is not supported.
Q2: Does the mid price update in real time?
A: Yes. The mid price is recalculated and updated in real time as the best bid price and best ask price change. When the market price fluctuates sharply, the mid price also changes quickly.
Q3: Why does the mid price differ from my filled price?
A: The actual filled price depends on the best price in the order book (Ask 1 for buys, Bid 1 for sells), while the mid price is the arithmetic average of the two. The mid price will always differ from the actual filled price. This difference equals half the bid-ask spread.
Q4: What is the difference between the mid price and the mark price?
A:
| Metric | Calculation | Purpose |
| Mid Price | (Bid 1 + Ask 1) ÷ 2 | Shows the midpoint of the current market quote |
| Mark Price | Calculated from multiple data sources (including the spot index, among others) | Used to calculate unrealized PnL and trigger liquidation |
Q5: Is the mid price still meaningful when the bid-ask spread is very large?
A: When the spread is large, the mid price can still serve as a rough reference for the market price, but note that the deviation between the actual filled price and the mid price will be more noticeable. We recommend trading during periods with better liquidity (smaller spreads).
Q6: Do all CFD trading pairs display a mid price?
A: Yes, as long as valid best bid and best ask quotes exist in the order book, the platform automatically calculates and displays the mid price.
Q7: Why is trading sometimes unavailable on MT5?
A: The MT5 trading server will undergo scheduled restart maintenance after market close every Friday. This process takes some time, during which trading features will be temporarily interrupted, and ongoing trades may also be affected. Service will automatically return to normal once maintenance is complete. We recommend planning your trades in advance to avoid inconvenience.
Terms & Conditions
- Reference liquidity is currently available only for some TradFi trading pairs. If a pair does not support reference liquidity, this announcement entry link will not be displayed on the pair's trading page.
- Reference liquidity will be unavailable while the market is closed. This is normal. Reference liquidity will automatically be displayed again once the market reopens.
- The MT5 trading server will undergo scheduled restart maintenance after market close every Friday, during which trading features will be briefly interrupted and ongoing trades may be affected. This is normal. Please plan your trades in advance accordingly.
- BingX reserves the right to final interpretation of this announcement, including any rule modifications, updates to terms, or cancellations.
- Multilingual translations of the product page rules may differ. If there is any discrepancy, the English original prevails.
- Any updates to the information above will be announced separately. If you still have questions about CFDs, contact our customer support at any time.Thank you for your understanding and support.
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Cryptocurrencies are highly volatile and may involve various risks, including market risk, project risk, technical risk, and compliance risk. You may incur investment losses. Note the risks and invest cautiously. BingX will continue improving its trading experience and product services. Thank you for your support and understanding.
BingX Operation Team
2026-07-23
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