Mark Price vs. Last Price: Why Derivatives Platforms Show Both

Common mistakes

• Assuming mark price is an executable quote.
• Assuming the last price is a personal fill or the official close.
• Building liquidation alerts from last price when the venue uses mark price.
• Applying one platform’s mark formula to another platform.
• Ignoring funding, fees, contract multiplier, and settlement method in P&L.
• Treating smoothing as protection against every gap or index failure.

How to reconcile a platform's prices

Begin with the product's contract specification and help page. Write down the exact formula for mark price, the index constituents, the funding or basis component, update frequency, and any guardrails. A perpetual futures mark may use an index plus a clamped premium, while another venue may use a fair-price model. The same label therefore does not guarantee the same number across platforms.

Next, align timestamps. The last price records the most recent eligible trade and can remain unchanged when no trade occurs. The mark price and index may continue updating from external markets. A comparison made a few seconds apart can create a false discrepancy, especially during volatile periods. Use a screenshot or export with timestamps and note whether the platform displays bid, ask, midpoint, index, last, or mark.

If a liquidation or unrealized-profit calculation is disputed, reconstruct the platform's stated method rather than substituting last price automatically. Record position size, entry price, maintenance-margin requirement, collateral, fees, funding, and the relevant mark-price snapshot. Liquidation engines can also use risk tiers and buffers that are not visible in a simplified formula. The contract terms and account statement are the controlling sources.

For performance records, choose and disclose a valuation convention. Closed trades can generally use actual execution prices and fees. Open positions may be valued with mark, midpoint, or another documented policy. Applying the same convention at every measurement date makes comparisons more meaningful, while switching between mark and last after seeing the outcome creates bias.

Common audit trail fields

For each disputed or reviewed valuation, save the contract symbol, venue, position side and size, entry price, last price, mark price, index price, best bid and ask, timestamp, funding status, maintenance tier, and account collateral. Exported values are preferable to a cropped screenshot because they preserve labels and precision. If the platform later revises its methodology, retain the version that applied at the event time.

When comparing venues, do not assume matching symbols represent identical contracts. Contract multiplier, settlement asset, index basket, funding interval, and liquidation rules can differ. Reconstruct each platform separately before attributing a difference to the mark-price formula.

Frequently asked questions

Can an order execute at the mark price?

Only if an executable order happens to be available at that price. The mark itself is normally a reference calculation, not an order-book quote.

Which price triggers liquidation?

It depends on the contract and venue. Use the current official rulebook and margin documentation.

Why can mark and last price diverge?

The last price can move with a single trade, while mark price follows its stated index and adjustment method. Thin liquidity, volatility, or venue dislocation can widen the difference.

Which price should appear in performance records?

Realized records should use actual fills and all applicable cash flows. For unrealized reporting, disclose whether the system uses mark, mid, bid, ask, settlement, or another valuation price.

Sources and Further Verification

• TradingView: Mark Price
• Investor.gov: Closing Price
• The relevant venue’s current contract specification, index methodology, margin policy, and liquidation rules