Updated 2026-07-25
Last price is simply the most recent trade printed on that one exchange. Mark price is a fair-value estimate built from a broader index of spot venues, usually with smoothing or a funding-basis adjustment. Unrealised profit and loss, margin checks and, critically, liquidations are evaluated against the mark price on most perpetual venues.
This distinction is the reason a violent wick on a single exchange does not always liquidate positions at that level: the wider index never moved that far, so the mark price never did either. It also means your liquidation price is a mark-price level, not a last-trade level, and that a chart of last prints can show a low your position survived. When you are reconciling why a position did or did not liquidate, always check the venue's mark price history rather than the candle chart.