Mark price
The mark price is the fair price a futures exchange calculates for a contract, mainly from an index of spot prices on several venues. It decides liquidations and your unrealised profit and loss, so one sharp trade on one exchange cannot liquidate everyone.
The last price is the price of the latest trade on that exchange; the mark price smooths it with prices from other venues. In a sudden wick the two can differ: on Binance’s Bitcoin perpetual on 4 June 2026, the last price fell to 61,345 while the mark price stopped at 61,412. A liquidation is checked against the mark price. Stop orders often follow the last price by default; most exchanges let you choose which one in the order settings.
Learn more: how to avoid liquidation.