A mark price is an exchange's reference value for an open derivatives position. Exchanges use it to calculate unrealized profit and loss and to evaluate whether a position meets its margin requirement. The calculation varies by venue and contract.
How It Differs From Other Prices
The last price records the most recent trade on one market. The index price combines prices from selected spot markets under an exchange's methodology. A mark price uses an index or other reference data, sometimes with a premium component or smoothing rule. Each exchange publishes its own calculation.
A mark price can reduce the effect of a brief trade far from the broader market reference. It cannot remove market risk, prevent all price gaps, or guarantee that an order will fill at the displayed mark.
Example
Suppose an exchange shows an index price of $65,000, a last trade at $65,120, and a mark price at $65,030. The mark price may differ because the venue applies its own basis or averaging inputs. The numbers here are illustrative. A trader should check the exchange's contract page for its formula and trigger rules.
A liquidation threshold can depend on mark price, margin mode, maintenance tier, fees, and position size. The last traded price alone may not show the value that the exchange uses to assess the position.
For venue-specific calculations, see Bybit's mark-price documentation and OKX's mark-price overview.