What to Check First When the Mark Price Fluctuates Abnormally
When the mark price deviates significantly from the last traded price, don't rush to add margin or cut losses. The first step is always to compare it with the index price — if the index price hasn't moved and only the mark price is jumping, you're looking at a mechanical deviation, not a real market direction. This applies to all traders holding perpetual contract positions.
Let's first explain why the mark price may behave "abnormally". Perpetual contracts do not expire or settle, so to prevent price manipulation, exchanges don't use the last traded price directly to trigger liquidations. Instead, they calculate a "mark price" as a reference. All major derivatives exchanges use a similar dual-price mechanism. The mark price factors in the spot index, futures order book, funding rate, and other elements. When it diverges from the last traded price, your liquidation threshold is effectively shifted.
Step 1: Overlay the Mark Price Line and Compare It with the Index Price
What to do: Display both the Mark Price and Index Price lines on your chart.
How to do it:
Bybit users: Switch to the Mark Price chart view in the chart menu, or add the Mark Price indicator for the corresponding symbol.
Deribit users: The mark price is shown by default; the index price can be found under the "Index" tab.
Most platforms: The mark price is typically shown as a yellow line, and the index price as a white or green line.
When you're done: You can see both lines on the same time axis and confirm the current deviation.
Step 2: Determine Which Direction the Deviation Comes From
What to do: Check whether the mark price suddenly spiked or dumped in isolation, or whether the index price followed the same move.
Case A — The index price moved in sync: This means the market is genuinely moving, and the mark price is simply following. In this case, you should assess your position direction and distance to liquidation instead of focusing on the mark price itself.
Case B — The index price stays flat while the mark price deviates on its own: This is a classic mechanical deviation, often occurring during low liquidity or extreme market sentiment. The mark price should not be used to make trading decisions in this situation, because it lags behind the real market movement.
When you're done: You can clearly identify the source of the deviation — whether the market is moving or the calculation mechanism is causing it.
Key reminder: If you see the mark price moving toward your liquidation price but the index price hasn't moved, do not add margin immediately. First figure out the cause of the deviation; otherwise you may lock up capital unnecessarily.
Step 3: Identify Where Your Liquidation Price Sits on the Mark Price
What to do: Find out which mark price level corresponds to your liquidation price — not which last traded price level.
How to do it:
Find the "Liquidation Price" on your positions page.
Go back to the mark price chart and see how much room remains between the current mark price and that level.
For Bybit users: For long positions, you need to look at the "lowest" mark price value during the period, and for short positions, the "highest" value, because the chart default may show the closing mark price only, potentially hiding intra-candle extremes that were touched.
When you're done: You should know the percentage distance from the current mark price to your liquidation price — this is your true safety cushion.
Step 4: Check Whether the Funding Rate Is in an Anomalous Period
What to do: See how long until the next funding rate settlement, and whether the predicted funding rate is unusually high.
How to do it:
Check the current funding rate in the "Funding Rate" area of your trading page.
If the next settlement is less than one hour away and the predicted rate's absolute value is significantly above recent averages (e.g., above 0.1%), part of the mark price fluctuation may come from funding arbitrage flows that distort the order book.
When you're done: You've ruled out or confirmed that "imminent funding rate settlement" is a factor affecting the mark price.
Prerequisites
Before going through the steps above, make sure you've enabled the "Show Mark Price" option in your trading interface. If you can't find it, search the platform's help center for "how to display mark price" — the entry point varies by platform but is always inside the chart settings.
Common Pitfalls
The most common mistake is looking only at the last traded price and using its fluctuations to assess risk. For example, if the last traded price is 3% away from the liquidation price, you might feel safe, but the mark price could be only 1.5% away. When the mark price reaches the liquidation price, the liquidation engine takes over your position — regardless of the last traded price. This misunderstanding leads to many "I got liquidated even though price didn't hit my stop" situations.
Risk Reminders
Capital risk: Blindly adding margin when the mark price is anomalous can lock up extra capital at unfavorable levels. When the deviation corrects, your average margin cost is higher, reducing your flexibility to adjust the position later.
Account risk: If the deviation persists in one direction (e.g., a persistent premium on perpetuals), repeatedly adding margin could trap you in a vicious cycle of topping up.
After completing these four steps, you've confirmed the source of the deviation and your current safety cushion. The next move depends on your assessment:
If the index price moved in sync → Return to normal position management and follow your stop-loss plan.
If the index price stayed flat and the mark price deviated alone → No action is needed; wait for the mark price to converge back toward the index price. This reversion typically happens within a few hours to a day, depending on how quickly the market calms down. You can set a price alert and reassess your position once the gap between the mark price and the index narrows to within 0.2%.
FAQ
Q1: What is the normal gap between the mark price and the last traded price? There is no universal standard. For liquid major coins (BTC, ETH), the gap is usually within 0.1%–0.3%. For altcoins or contracts with thin liquidity, it can be 1%–2%. If the gap suddenly doubles and persists for more than two hours, it suggests a problem with market depth or the arbitrage mechanism, and you should consider reducing or closing your position.
Q2: When the mark price fluctuates abnormally, which price should I reference for stop-loss orders? The trigger condition depends on your stop order type. For a stop-limit or stop-market order, you can typically choose the trigger reference when setting it up — you can select either mark price or last traded price as the trigger. We recommend choosing mark price as the trigger, so your stop logic aligns with the liquidation logic. This avoids the situation where "the last traded price hits but the mark price hasn't, so the stop didn't trigger," or the reverse. The setup interface differs by platform, so always double-check the trigger price type before placing the order.
