Cross Margin
Cross margin shares the entire account balance across all open positions to prevent liquidation, unlike isolated margin which limits risk per trade.
Key Takeaways
- Cross margin pools your entire account balance as shared collateral across all open positions, so unrealized profits from one trade can offset losses on another and reduce your overall liquidation risk.
- Unlike isolated margin, where each position has its own collateral and can be liquidated independently, cross margin means a single catastrophic trade can drain your full account balance and trigger liquidation of every open position.
- Most major exchanges default to cross margin for perpetual futures trading because it improves capital efficiency, but traders should understand the tradeoff between per-position safety and portfolio-wide risk.
What Is Cross Margin?
Cross margin is a margin mode used in cryptocurrency derivatives trading where the full available balance of a trader's account serves as collateral for all open positions simultaneously. Rather than assigning a fixed amount of margin to each individual trade, cross margin creates a shared pool: every unit of collateral backs every position at once.
This approach contrasts with isolated margin, where each position receives a dedicated allocation of collateral and can only be liquidated using that specific allocation. Cross margin is sometimes called "spread margin" because risk is spread across the entire account rather than contained within individual trades.
Most exchanges including Binance, Bybit, and dYdX default to cross margin for futures contracts. The mode is especially popular among experienced traders who run hedged portfolios, because offsetting positions naturally reduce net risk under a shared collateral model.
How It Works
To understand cross margin, consider how an exchange evaluates your account in real time. The exchange continuously calculates two values:
- Margin Balance: your wallet balance plus the sum of unrealized profit and loss across all open positions
- Total Maintenance Margin: the sum of each position's notional value multiplied by the maintenance margin rate for its size tier
As long as your margin balance exceeds the total maintenance margin, your positions remain open. The moment margin balance drops below the maintenance threshold, the exchange's liquidation engine activates.
Margin Balance Calculation
The core formula the exchange applies on every price tick:
Margin Balance = Wallet Balance + Σ(Unrealized PnL of each position)
Total Maintenance Margin = Σ(Position Notional Value × MMR for that tier)
Liquidation triggers when:
Margin Balance < Total Maintenance MarginConsider a trader with $15,000 in their futures wallet who opens two positions:
- Position A: long BTC worth $50,000 notional, currently at +$3,000 unrealized profit
- Position B: long ETH worth $30,000 notional, currently at -$2,000 unrealized loss
Under cross margin, the margin balance is $15,000 + $3,000 - $2,000 = $16,000. The profit from Position A directly subsidizes the loss on Position B, keeping the combined account well above the maintenance requirement.
Under isolated margin, Position B would be evaluated solely against its own allocated collateral. If only $3,000 was allocated to it, a $2,000 loss would leave it dangerously close to liquidation price, regardless of how well Position A is performing.
Tiered Maintenance Margin Rates
Exchanges use a tiered system where maintenance margin rates (MMR) increase as position size grows. This limits extreme leverage on large positions and protects the exchange from liquidation cascades:
| Position Size Tier | Typical MMR | Effective Max Leverage |
|---|---|---|
| Small (Tier 1) | 0.4% to 0.5% | 100x to 125x |
| Medium | 1% to 5% | 10x to 50x |
| Large | 10% to 50% | 2x to 5x |
A small BTC perpetual position might only require 0.4% maintenance margin, while a $100 million position could require 25% or more. These tiers apply identically whether the trader uses cross or isolated margin: the difference is only in which collateral backs the requirement.
Cross Margin vs. Isolated Margin
The choice between cross and isolated margin defines how risk flows through a trader's account. Each mode suits different strategies and risk tolerances:
| Aspect | Cross Margin | Isolated Margin |
|---|---|---|
| Collateral scope | Entire account balance shared | Fixed amount per position |
| Liquidation trigger | Account equity below aggregate maintenance margin | Individual position margin below its own maintenance requirement |
| PnL interaction | Profit on one position offsets loss on another | Each position's PnL is independent |
| Maximum loss | Entire account balance | Only the margin allocated to that position |
| Liquidation price | Farther from entry (more buffer) | Closer to entry (less buffer, but capped loss) |
| Best for | Hedged portfolios, correlated pairs, experienced traders | Speculative trades where the trader wants a hard loss cap |
An important mechanical difference: cross margin has no fixed liquidation price because the liquidation point depends on all positions' combined PnL. The "estimated liquidation price" shown by exchanges is a reference only and shifts as other positions move. Isolated margin produces a deterministic liquidation price calculated at position entry.
Portfolio Margin
Portfolio margin is an advanced variant that builds on cross margin by recognizing hedging relationships between correlated positions across different instruments. Standard cross margin pools collateral but still calculates margin requirements for each position independently and sums them. Portfolio margin estimates the worst-case portfolio loss under simulated price shocks (stress tests).
For example, if a trader holds a long BTC future and a short BTC call option, standard cross margin requires full margin on both positions. Portfolio margin recognizes that these positions partially offset each other and reduces the total margin requirement accordingly. This frees capital for additional trades.
Binance's Portfolio Margin uses a unified maintenance margin ratio (uniMMR) that spans cross margin, USDS-M futures, and COIN-M futures as a single joint collateral pool, supporting hundreds of cryptocurrencies as collateral. Bybit's Unified Trading Account (UTA) offers similar functionality, consolidating spot, derivatives, and options under one margin umbrella.
Use Cases
Hedged Positions
A trader who is long BTC/USDT and short ETH/USDT as a relative-value trade benefits from cross margin because the two positions partially hedge each other. If the broader market drops, losses on the BTC long may be offset by gains on the ETH short, keeping the combined account healthy. Under isolated margin, the BTC long could be liquidated even while the ETH short is profitable.
Market Making
Market makers maintain many simultaneous positions across multiple trading pairs. Cross margin allows them to use a single capital pool rather than fragmenting collateral across dozens of isolated positions. This capital efficiency is critical when operating on thin margins across high volumes.
Basis Trading
Basis trades involve going long spot and short perpetual futures (or vice versa) to capture the funding rate difference. Because the two legs are directionally opposite, cross margin recognizes the reduced net exposure and keeps maintenance requirements lower than two separate isolated positions would demand.
Capital-Efficient Speculation
Even for single-position traders, cross margin provides a larger buffer against temporary price wicks. A flash crash that briefly dips below an isolated-margin liquidation price would liquidate that position, while the same price movement under cross margin might leave the account safely above maintenance requirements thanks to the full account balance acting as collateral.
Risks and Considerations
Portfolio-Wide Liquidation
The most significant risk of cross margin: one catastrophic position can drain the entire account. If a leveraged trade moves sharply against you, the exchange draws from your full balance to cover the loss. If the margin balance across all positions falls below the total maintenance requirement, the liquidation engine may close every open position, not just the losing one.
Under isolated margin, the same losing trade would only consume its allocated collateral. The rest of the account remains untouched. This hard loss cap is why many risk-conscious traders prefer isolated margin for speculative positions.
Correlation Risk
Cross margin works well when positions are diversified or hedged. During market-wide events like a flash crash or liquidation cascade, multiple positions can move adversely at the same time. Correlated losses across the portfolio compound rapidly, eroding the shared collateral pool far faster than any single position would suggest.
Over-Leveraging Temptation
The larger apparent buffer of a cross-margin account can encourage traders to take on more risk than intended. When the full balance acts as collateral, it feels safe to open additional positions or increase leverage. But each new position increases the total maintenance margin requirement and reduces the effective buffer for every existing position.
No Fixed Liquidation Price
Because the liquidation price under cross margin depends on all positions' combined PnL and the total account balance, it shifts constantly. A new position, a deposit, a withdrawal, or a price change on any other position changes the liquidation price for every position. This makes risk management more complex than the deterministic liquidation price offered by isolated margin.
Liquidation Mechanics
When cross-margin liquidation triggers, the exchange typically closes the most-losing position first. If that is insufficient to restore the margin ratio, additional positions are closed until the account is above maintenance. If positions are closed at prices worse than the bankruptcy price, the exchange's insurance fund covers the deficit. When the insurance fund is insufficient, auto-deleveraging (ADL) activates, forcibly reducing profitable counterparty positions.
Why It Matters
Cross margin is the default mode on most cryptocurrency derivatives exchanges because it offers the best capital efficiency for traders managing multiple positions. Understanding when to use cross margin versus isolated margin is fundamental to margin trading risk management. For traders exploring decentralized alternatives, on-chain perpetual protocols bring cross-margin mechanics to decentralized finance, where transparent margin calculations replace centralized exchange risk engines.
As unified trading accounts become standard across the industry, the line between cross margin and portfolio margin continues to blur. Bybit, Binance, and decentralized protocols are converging on margin systems that combine spot, derivatives, and options under a single cross-collateral umbrella, giving traders more flexibility but also demanding deeper understanding of how shared collateral amplifies both opportunity and risk.
This glossary entry is for informational purposes only and does not constitute financial or investment advice. Always do your own research before using any protocol or technology.