Market data
One contract, three prices: last, index and mark
At a glance
Last price records a trade, index price represents a specified reference basket, and mark price is a calculated risk reference. They can differ. A displayed mark is not an offer at which you can necessarily close.
On this page
A contract screen can show several prices at once. The problem is not simply choosing the largest or most recent-looking number. Each is attached to a different question: what traded, what reference is calculated, and what bids or asks are available now?
Separate a print from a calculation
Bybit's mark-price documentation explains its calculated reference and how it differs from the last trade. The precise method can change and varies by product. For liquidation, read the margin-mode rules as well: an account-level test is not always reducible to a single position price.
The order book, meanwhile, shows available buy and sell interest. Those quotes can change or lack enough quantity for your exit. Neither a last trade nor a mark value guarantees the next execution.
A discrepancy without an arithmetic error
Take a hypothetical linear long of two units entered at 100 USDT. At one observation, last is 101, index is 100.70 and mark is 100.80. Ignore costs.
| Reference used for illustration | Price | Calculated open price profit |
|---|---|---|
| Last | 101.00 | 2.00 USDT |
| Index | 100.70 | 1.40 USDT |
| Mark | 100.80 | 1.60 USDT |
Each calculation is quantity × (reference − entry). None is the proceeds of a completed sale. If two units actually sell at an average 100.60, gross realized price profit is 1.20 USDT, before costs. A displayed 1.60 based on mark was not a promise of 1.60 on exit.
Compare like timestamps
Before reporting an unexplained difference, record contract, account mode, reference label, timestamp and timezone. A spot index from one moment and a futures last price several seconds later are not a controlled comparison. Match the chart's reference setting too; candle highs from one series do not reveal another series' intrabar path.
Do not label a difference manipulation without evidence. Different methods, asynchronous observations and market movement are possible explanations that require investigation, not automatic conclusions.
Use each number for its stated job
Inspect actual fills for completed trading results and the platform's defined risk reference for margin monitoring. For a conditional exit, identify which price triggers it, then separately inspect the resulting order. Our stop-order article walks through that second distinction.
CoinFom editorial note: research, writing, translation and review used AI assistance. No live transaction was performed for this article. Numerical examples are hypothetical and do not demonstrate returns. Sources checked September 26–27, 2026. Educational content, not personalized advice. See About CoinFom, our editorial and affiliate policy, or send a correction. CoinFom may earn referral commissions on other pages; this article contains no signup link.