What Is Cross Margin?
Cross margin uses your entire available account balance as collateral for all open positions. If one position starts losing, it draws margin from your total balance. This provides a larger buffer against liquidation but means a single bad trade can drain funds earmarked for other positions.
How Cross Margin Works
With $10,000 in your account and a $5,000 cross-margin long, the remaining $5,000 serves as additional buffer. Your liquidation price is further away than it would be with isolated margin. However, if the trade goes deeply against you, it can consume your entire $10,000 balance.
Why It Matters for Traders
Cross margin is preferred by experienced traders running correlated or hedged positions where one position's loss is offset by another's gain. It's dangerous for directional bets because a single liquidation wipes the entire account. New traders should default to isolated margin until they fully understand portfolio-level risk management.
How It Works on CEX Perps
On centralized perpetual futures venues, cross margin shows up in the position panel, the funding timer, or the liquidation engine rather than as a separate product. Traders usually check it next to mark price, margin mode, and open interest so they do not size a trade from last price alone.
Example numbers only (not a live quote): if you hold a $10,000 notional long with 5x leverage, your initial margin is about $2,000. A move against you of roughly 20% of that notional can push the position near maintenance margin depending on the venue formula. Always read the venue's own liquidation rule before you size.
Formula and Worked Example
Use this only as a labeled example. It is not a live market print.
- Notional = coin size × mark price.
- Initial margin ≈ notional ÷ leverage.
- Distance to liquidation depends on maintenance margin, fees, and whether you use cross or isolated margin.
Example: 0.1 BTC long, mark $60,000, leverage 10x → notional $6,000, initial margin about $600. If maintenance margin is near 0.5% of notional, a modest adverse move can close the trade even when your thesis is still intact.
Common Mistakes
- Treating a single print of cross margin as a trade signal without checking funding, open interest, and your liquidation price.
- Mixing venue conventions (coin-margined vs USDT-margined, cross vs isolated) and reading the wrong mark.
- Copying example numbers from a glossary into live size without checking the current book depth and fee schedule.
- Ignoring related terms that change the meaning of the print on a given day.
