Mark Price vs Last Price: What Traders Need to Know

Mark price is the reference price a crypto derivatives exchange uses to value open positions and trigger liquidations. It is built from an index of spot prices on several exchanges, so it moves more smoothly than the last traded price on one order book. Last price is simply where the most recent trade printed, and index price is the average spot price behind the mark.

If you trade crypto derivatives such as perpetual futures, all three numbers sit on the same screen and can disagree sharply in fast markets. This guide explains each price, why exchanges rely on mark price, and how it decides your liquidation price, unrealised P&L and stop triggers.

Quick answer: Mark price is a fair-value price that crypto derivatives exchanges calculate from a spot index across several exchanges plus a smoothed premium or basis component. Exchanges use mark price, not the last traded price, to calculate unrealised profit and loss and to trigger liquidations, so a single wick on one order book does not liquidate positions.

---

Key facts about mark price

What is the last price?

The last price is the price at which the most recent trade executed on a specific exchange's order book. It is the number most charts plot by default, and it changes every time a buyer and seller are matched.

Because it comes from a single order book, a large market order on a thin book can push the last price far from where the asset trades elsewhere, then let it snap back seconds later. The bid-ask spread and slippage on your fills come from the same mechanics.

What is the index price?

The index price is a weighted average of the asset's spot price across several major spot exchanges. Its job is to represent where the underlying asset really trades, independent of any one venue.

Exchanges usually weight a handful of liquid spot markets and exclude or cap any source that deviates too far or stops updating, so one exchange having a bad minute barely moves the index.

What is the mark price?

The mark price is the price an exchange treats as the fair value of a derivatives contract. It starts from the index price and adds a component that reflects the normal gap between the contract and spot, smoothed over time so that it cannot be pushed around by a single trade.

A perpetual future can trade above or below spot for long periods, which the funding rate exists to correct. The mark price reflects that gap in a stable way without copying every tick of the last price.

Mark price vs last price vs index price at a glance

Why do exchanges use mark price?

Exchanges use mark price so that liquidations and account values depend on fair value rather than on one trade. That serves two purposes: protection against manipulation and wicks, and a fairer picture of unrealised profit and loss.

Protection against manipulation and wicks

If liquidations used the last price, a trader with enough capital could push a thin book down for a few seconds, trigger a wave of long liquidations, and buy the forced selling cheaply. Even without bad intent, one large market order can print a wick far below fair value.

The chart below shows exactly that situation. A sudden wick takes the last traded price down to 96.90, below a long position's liquidation level at 98.00, while the smoothed mark price barely reacts and stays above the level, so the position is not liquidated.

The candles around the wick trade near 100.5 to 101, and the mark price line runs through that range. One thin book cannot drag a multi-exchange index to 96.90, so the mark price ignores the single bar.

Fair unrealised P&L

If accounts were valued at the last price, equity would jump with every wick and margin checks would fire on numbers that did not reflect a tradable market. Valuing positions at the mark price keeps the account value stable and realistic.

How is mark price calculated?

Mark price is calculated in two steps on most venues: build an index of spot prices, then add a smoothed measure of how far the contract normally trades from that index. The exact formula, inputs and averaging window vary by exchange.

1. Build the index price. The exchange takes spot prices from several major exchanges, weights them, and filters out outliers or stale sources.
2. Measure the premium or basis. The exchange compares the contract's own price (often the mid of the best bid and ask) with the index to find the gap.
3. Smooth the gap. The gap is averaged over a period, for example a moving average over several minutes, so a brief spike does not count fully.
4. Combine them. Mark price is roughly the index price plus the smoothed premium. Some venues take a median of several candidate prices instead, which also discards an outlier.

For dated futures, many venues use a fair-basis term that shrinks toward expiry, because the futures price converges to spot at settlement. Check your exchange's documentation, since methods are not standard.

How does mark price decide your liquidation price?

On most crypto derivatives exchanges, a position is liquidated when the mark price, not the last price, reaches the liquidation price. The liquidation price is the level where your remaining margin falls to the maintenance margin requirement. Our guide to liquidation in trading covers the full mechanics, and the margin call guide explains the related warning stage.

Worked example: a long that survives the wick

Here is a simplified example with illustrative numbers. Fees and funding are ignored, and real exchanges use their own formulas.

• You buy 100 contracts at 100.00, so the position notional is 100 x 100.00 = 10,000 USD.
• You post 250 USD of initial margin, which is 2.5% of the notional (40x leverage).
• The maintenance margin rate is 0.5%.

A simplified liquidation price for a long is entry x (1 minus initial margin rate plus maintenance margin rate):

100.00 x (1 minus 0.025 plus 0.005) = 100.00 x 0.98 = 98.00

Check the arithmetic: at 98.00 the loss is 100 x (100.00 minus 98.00) = 200 USD. That leaves 250 minus 200 = 50 USD of margin, which is about 0.5% of the 9,800 USD notional, the maintenance level.

Now the wick prints. The last price touches 96.90 for one candle. Valued at the last price, the loss would be 100 x 3.10 = 310 USD, more than the 250 USD of margin, and the position would be gone. But the mark price on that candle stays near 100.70, far above 98.00, so nothing happens and the trade continues.

The flip side: if spot exchanges really trade down to 98, the index and the mark price fall too, and the position is liquidated. Mark price protects you from a glitch, not from being wrong. Lower leverage, a planned stop-loss and sensible size are the real protection, as covered in never get liquidated again.

Mark price and margin mode

How much of your account is exposed when the mark price reaches liquidation depends on your margin mode. The chart below shows a 10,000 USD position: with 1,000 USD of isolated margin, the loss stops at 1,000 USD and the position is liquidated at a 10% fall, while on cross margin the loss keeps growing because the position draws on the whole account balance.

Under cross margin, positions share the balance, so the liquidation price moves as other positions win or lose. The cross vs isolated margin guide compares both modes.

How does mark price affect unrealised P&L?

Unrealised P&L on most derivatives venues is calculated as position size x (mark price minus entry price) for a long, and the reverse for a short. Realised P&L, once you close, uses your actual fill price.

Using the example above, on the wick candle:

• Unrealised P&L at the mark price: 100 x (100.70 minus 100.00) = +70 USD
• What the last price would have shown: 100 x (96.90 minus 100.00) = minus 310 USD

So your displayed P&L can differ from what you get on close: a market exit fills at the order book price plus slippage, not at the mark. The gap is usually small, but it can matter in fast markets.

Should your stop-loss trigger on last price or mark price?

Many exchanges let you choose whether a stop order triggers on the last price or the mark price, and some also offer the index price. Neither choice is right for every trade; the right one depends on what you want the stop to do.

A practical routine:

1. Decide what the stop protects. A mark price trigger filters noise; a last price trigger fires on any trade at your level.
2. Check how far mark and last price drift on your instrument during volatile hours.
3. Keep stops well inside your liquidation price.
4. Choose the order type. A stop-market fills at the next available price; a stop-limit controls price but may not fill (see order types).

Gianluca Pizzituti, Velotrade's co-founder, prefers limit orders for entries. A protective stop is different: its job is to get you out, so check how your chosen trigger and order type behave before you rely on them.

Common mistakes with mark price

• Reading only the last price chart. Liquidation is measured against the mark, so display the mark price line.
• Treating mark price as a guarantee. It filters single wicks, not sustained moves.
• Ignoring funding. On perpetuals, funding payments change your margin and can move your liquidation price.
• Using maximum leverage. It puts liquidation close to entry, where ordinary volatility reaches it. Broker disclosures and academic studies consistently find that most retail day traders lose money, and leverage magnifies losses.

Can AI help with mark price and liquidation risk?

AI tools can help with screening for instruments where mark and last price often diverge, reviewing a journal for stops hit by wicks, or backtesting trading strategies with different stop triggers. See AI trading strategies for what these approaches can and cannot do.

AI does not remove the risk of leverage or liquidation. A model trained on past data cannot know when the next fast market comes, so size, stops and leverage still need human judgement.

How does this apply in a prop trading challenge?

Velotrade, a multi-asset prop trading firm, offers simulated evaluations with 100+ crypto instruments that trade 24/7, alongside forex, stocks, index ETFs and commodities. Velotrade does not use a liquidation engine or margin calls as its account rules. Its hard limits are the daily loss limit, which resets at 00:30 UTC from the higher of balance or equity (5% on CLASSIC 2-Step, 4% on CLASSIC 1-Step, 3% on PRO 1-Step), and a static maximum drawdown. Position size is limited only by leverage, for example BTC at 10x in the challenge and 5x once funded; see instruments for every figure.

The lesson still applies: guard against noise with a planned stop and against real moves with sensible size. For price comparison, Velotrade's FAQ points traders to the matching KuCoin USDT perpetual symbols on TradingView. See prop firm leverage and the challenges page for the full rules.

This article is educational only and is not investment advice.