Three prices can describe different things.
The last traded price records the most recent match in a particular market. An index price combines underlying reference-market inputs according to the provider’s method. A mark price is a calculated reference used in derivatives valuation and risk checks. These values need not move in exact lockstep.
| Price | Question it helps answer |
|---|---|
| Last traded price | At what price did the latest reported trade match? |
| Index price | What does the venue’s underlying reference calculation show? |
| Mark price | What reference is being used for the venue’s derivatives valuation or risk process? |
A mark is not a resting bid or ask. An order cannot assume it will execute there merely because a position panel displays it.
The display basis changes an unrealized estimate.
Consider a hypothetical linear long of 0.200 BTC entered at 49,800 USDT. Suppose mark is 50,000 and last is 50,020. Excluding commissions and funding:
| Reference used | Calculation | Unrealized price P&L |
|---|---|---|
| Mark | 0.200 × (50,000 − 49,800) | 40 USDT |
| Last | 0.200 × (50,020 − 49,800) | 44 USDT |
The 4 USDT difference comes entirely from the reference price. It is not proof that four dollars disappeared or that either display contains a completed close. Realized proceeds depend on actual fills and costs. This simple linear calculation does not describe inverse-contract P&L.
Risk checks and chart candles can use different inputs.
Bybit documents a mark-price calculation and uses mark in its derivatives risk process. The full liquidation condition also depends on account and margin mode. A last-price candle alone does not reproduce the account’s maintenance-margin calculation.
When investigating a liquidation or an unexpected account-equity value, inspect the provider’s mark data, wallet state and margin rules. A terminal’s daily protection reference is another calculation with its own baseline and update timing; it should not be equated with an exchange liquidation threshold.
A trigger reference is another explicit choice.
Where the venue and adapter support it, a conditional instruction may reference Last, Mark or Index. The trigger determines when an instruction becomes eligible; the eventual execution depends on the order type and available market. A stop trigger price is not automatically a guaranteed fill price.
Two otherwise similar stops can trigger at different times if their reference types differ. Read the submitted trigger type alongside the trigger value and account context. Do not infer it from whichever chart is currently visible.
Compare like with like.
- Confirm the exchange, product category and contract symbol.
- Check whether the chart is showing Last, Mark or another series.
- Read the position panel’s P&L basis and settlement currency.
- Compare timestamps and feed status before comparing individual ticks.
- For a completed close, reconcile execution prices and fees rather than an unrealized estimate.
Spot and futures prices can also differ because they are separate markets. Different browsers may hold different saved display preferences. Those possibilities should be checked before assuming a chart or account calculation is incorrect.