Open a Futures position and you may notice something odd: it shows a small unrealised profit or loss the instant it is filled, even though the market has not moved. Or the chart shows one number while the position panel shows another.

This is not an error. A Futures contract has more than one price attached to it, because different calculations need different reference points, and the number recording the most recent trade is not always the one used to measure what a position is worth or when it is at risk.

What Is Last Price?

The Last Price is the most recent price at which the contract actually traded on XT Exchange — a record of a completed transaction between a buyer and a seller.

Because it reflects individual executions, it can move quickly. Each fill updates it, and in a thin book a single large order can push it several steps away before it snaps back. That makes the Last Price an accurate record of what just happened — but not automatically the right reference for the calculations that follow, and on XT Exchange it is not the one used for the most consequential ones.

What Is Mark Price?

The Mark Price is a reference price XT Exchange uses for specific Futures calculations. XT Exchange states its purpose plainly: perpetual contracts employ a mark price system to avoid unnecessary liquidations when a market is illiquid or being manipulated.

For perpetual contracts, XT Exchange states the Mark Price equals the underlying index price plus a decaying funding basis rate. The Index Price is itself an aggregate, drawn from the spot prices of multiple top-tier exchanges and weighted by each venue’s 24-hour volume, so no single exchange can disproportionately affect it.

XT Exchange calculates the Mark Price as the median of three inputs: two derived price measures and the contract price. A median sets an extreme outlier aside rather than pulling it into the result. XT Exchange documents further safeguards, including taking the Mark Price from one derived measure where it diverges from the index by more than 1%, and temporary latest-traded-price protection where a stable reference source is unavailable. The goal is stability for risk calculations, not fidelity to the very last trade.

Why Mark Price and Last Price Can Differ

• A premium or discount on the contract. A perpetual can trade above or below the spot index for a period, and the Mark Price is anchored to that index.
• Fast-moving markets. The Last Price updates with every execution; a reference built from aggregated inputs is, by design, slower to move.
• Thin liquidity and wider spreads. A modest order can move the Last Price a long way in a thin book; the aggregated index is far harder to shift.
• One execution versus a methodology. The Last Price is a single data point; the Mark Price combines several.

A gap between them is ordinary market behaviour, not a malfunction.

Where the Difference Matters

Unrealised P&L. XT Exchange states that the mark price mechanism affects the forced liquidation price and unrealised P&L, and that realised P&L is not affected. Hence the small gain or loss when a position opens: the Mark Price deviates slightly from the fill price. XT Exchange notes this is normal and does not mean money has been lost.

Liquidation. The most important one. Forced liquidation is triggered when the Mark Price reaches the liquidation price, not when the Last Price does — XT Exchange uses the mark price methodology specifically to avoid liquidations caused by a lack of liquidity or manipulation. Liquidation is irreversible, and traders cannot control its execution time or price.

Margin and funding. XT Exchange documentation states that Mark Price is used to calculate margin requirements. It also sizes funding payments: XT Exchange calculates the funding fee as position value multiplied by the funding rate, where position value is contract quantity times the Mark Price.

Conditional orders. Stop-loss and take-profit orders differ again. For standard price-based TP/SL triggers, XT Exchange supports Mark Price, Index Price and Latest Price. Advanced settings may also offer a price-fluctuation-based trigger. The selected reference can differ from the Mark Price used for liquidation.

One distinction deserves emphasis: a trigger condition is not an execution price. When a market-mode stop-loss triggers, the system executes at the best available price, and XT Exchange states the actual price may vary with market conditions. XT Exchange also notes these orders do not freeze the position before triggering, and may fail if the position exceeds the market order’s maximum quantity limit or margin is insufficient at trigger time.

A Simple Illustrative Example

Hypothetical illustration only. The numbers are invented and describe no real market or outcome.

Imagine a contract where recent trading has clustered around 100. A large market sell order hits a thin order book and fills down to 97, so the Last Price reads 97.

The Mark Price, anchored to an index drawn from several spot venues, may still read close to 100, because the broader market has not moved. A trader watching only the Last Price might think the position is closer to liquidation than it is. A stop-loss triggering on Latest Price could activate on that 97 print, while one set to Mark Price would not — neither setting is inherently correct; they answer different questions.

Common Misunderstandings

“My P&L must be wrong because it differs from Last Price.” Unrealised P&L is calculated against the Mark Price, so a difference is expected. Realised P&L, booked when the position closes, is not affected.

“A brief price wick always triggers liquidation.” Liquidation is assessed against the Mark Price, and a single sharp print does not necessarily move it far — which is what the methodology is designed to achieve. That reduces one cause of liquidation; it does not remove liquidation risk, and a genuine market move will move the index too.

“A stop-loss automatically uses the same price reference as liquidation.” It does not, unless Mark Price is selected as the trigger type. Stop-loss and take-profit orders can trigger on Mark Price, Index Price or Latest Price.

“Mark Price predicts where the market will trade next.” It does not. It is a reference for current calculations, derived from existing market data, with no forecasting function.

“The latest price is the only number that matters.” The Last Price tells you what just traded; the Mark Price governs unrealised P&L, liquidation and funding size. Both matter, for different reasons.

What to Check Before Opening or Managing a Futures Position

• The current Last Price, for where the contract is trading now.
• The current Mark Price, under [Information] → [Index Price], then [Mark Price].
• The Index Price, at the top of the USDT-M or Coin-M Futures page, or under [Futures Info] → [Futures Index].
• The trigger reference selected for any conditional order.
• The estimated liquidation price, remembering it is assessed against the Mark Price.
• Margin mode, leverage and funding exposure, since funding is charged periodically and sized using the Mark Price.

Two Different Metrics, One Essential Skill

Mark Price and Last Price are not competing versions of the same figure. One records the most recent transaction; the other is a deliberately steadier reference used for unrealised P&L, margin, funding size and liquidation.

Knowing which is which lets a trader read a position more accurately: why the opening P&L is not zero, why a wick is not automatically a liquidation event, and why a stop-loss and a liquidation can respond to different numbers. That is a reading skill, not a protection. It does not reduce market risk, and no price reference or order type removes the possibility of liquidation.

About XT Exchange

Founded in 2018, XT Exchange is a global digital asset trading platform serving more than 12 million registered users across over 200 countries and regions. Its services span spot, margin and futures trading, TradFi market exposure, a real-world asset marketplace, and everyday payments through XT Pay. Guided by Xplore Crypto Trade with Trust, XT Exchange enters its ninth year with Build the NeXT, reflecting its focus on trust, broader market access, and practical uses for digital assets.

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Disclaimer: XT Exchange reserves the right, at its sole discretion, to modify, amend, or cancel this announcement at any time for any reason without prior notice.