Introduction
In Portfolio Margin Mode, you can seamlessly trade five different products—spot, margin, futures, perpetual swaps, and options—by simply transferring your assets into a cross margin account. This setup allows for the sharing of margin across different derivatives that share the same settlement currency. During risk calculation, profits and losses in the same currency can offset each other.
A key feature is that all positions sharing a settlement currency are evaluated together for risk. If the equity in that currency becomes insufficient, it could lead to the partial liquidation, full liquidation, or even a total loss of all equity in that currency for all related positions. To isolate risk, traders can also use an isolated margin mode for specific positions.
Key Account Fields
Understanding your account balance fields is crucial for effective risk management. Below are the essential terms and their meanings.
- Equity (eq): The total equity of a specific currency in your account, combining both cross margin and isolated margin positions. It is calculated as: Currency Balance + Cross Margin P&L + Isolated Margin Balance + Isolated Position P&L + Options Market Value.
- Available Margin (availEq): The amount of a specific currency currently available to open new cross margin positions for leverage, futures, perpetual swaps, or as an option seller. Formula: Max(0, Cross Margin Balance + Cross Margin P&L - Frozen Amount).
- Available Balance (availBal): The amount available to open new isolated margin positions, act as an option buyer, or place spot sell orders. Note: This field is used for order calculations and is not displayed in the general asset overview.
- Frozen Balance (frozenBal): The amount of a specific currency currently locked due to open orders or existing positions, encompassing both cross and isolated margin orders.
- Unrealized P&L (upl): The sum of all unrealized gains and losses for leverage and contract positions settled in a specific currency, including both cross and isolated margin positions.
- Notional Leverage (notionalLever): The overall leverage at the currency level, calculated as Total Position Value / (Cross Margin Balance + Cross Margin P&L). The method for calculating the position value varies by product type (e.g., coin-versus USDT-margined contracts, margin trading, options).
- Maintenance Margin Ratio (mgnRatio): A risk indicator for a specific currency. It is calculated as: (Cross Margin Balance + Cross Margin P&L - Sell Order Amount - Option Buy Order Requirement - Isolated Margin Opening Requirement - All Order Fees) / (Maintenance Margin + Liquidation Fee). This includes fees and maintenance margins for all open orders to prevent a sudden shift in account risk upon order execution.
- Account Equity in USD (eqUsd): The total net value of all currency assets in the account, converted to fiat value. It is the sum of each currency's equity multiplied by its index price or a derived USDT price.
Trading Rules Explained
In Portfolio Margin Mode, you can choose between cross and isolated margin strategies. Cross margin allows all positions with the same settlement currency to share collateral and offset profits and losses. Isolated margin isolates the risk for each individual position.
Cross Margin Order Validation
- When opening positions for futures, perpetual swaps, option selling, or margin trades in cross margin mode, the available margin for that currency must be greater than or equal to the required amount for the order.
- For spot trades or option buying in cross margin mode, the available balance for that currency must meet or exceed the order's requirement.
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Note: The available balance refers to the amount that can be used for isolated margin openings, spot trading, and option buying.
Example Scenario: Assume a user's account has the following BTC cross margin positions and orders:
| Position | Type | Direction | Leverage | Position Margin (BTC) | Order Margin (BTC) | Unrealized P&L (BTC) | Maintenance Margin Rate |
|---|---|---|---|---|---|---|---|
| BTCUSDT Margin | Isolated | Long | 5x | 100 | 200 | 10 | 1% |
| BTCUSDT Margin | Cross | Long | 5x | 100 | 200 | 10 | 1% |
| BTCUSD Quarterly | Cross Futures | Long | 1x | 10 | 20 | 5 | 1% |
- Placing a New Cross Margin Order: To open a new 5x leveraged long with a 200 BTC order, the required margin is 200 / 5 = 40 BTC. The total frozen amount is 530 BTC. The available margin is 185 BTC. Since 185 > 40, the order is successful.
- Failed Order Example: Placing a large futures order requiring 200 BTC of margin would fail because the available margin (185 BTC) is less than the requirement.
Cross Margin Trading Details
Key Position Fields for Margin Trading
- Position Quantity (pos): The amount of positive assets in the position (excluding margin).
- Available to Close (availPos): The amount of positive assets available for closing the position.
- Liability (liab): Initial borrowed amount plus accrued interest. For long positions, the liability is in the quote currency; for short positions, it's in the base currency.
- Interest (interest): Interest that has accrued but not yet been deducted.
- Average Opening Price (avgPx): The volume-weighted average price of all fills that have built the position.
- Estimated Liquidation Price (liqPx): The estimated price at which the position would be liquidated. Note: This may not be calculable in complex portfolios with options or multiple currency pairs.
- Unrealized P&L (upl): The current unrealized profit or loss of the position, calculated differently based on the margin currency and trade direction.
- Return on Equity (uplRatio): P&L / Initial Margin.
- Initial Margin Requirement (imr): The collateral required to open and maintain the leveraged position.
- Maintenance Margin Requirement (mmr): The minimum amount of equity that must be maintained in the position to avoid liquidation.
Opening a Margin Position
In a pair like BTC/USDT, you can choose either currency as collateral for a long or short trade. For instance, a 10x long on 1 BTC using BTC as collateral requires 0.1 BTC in available margin. Upon execution, the position holds 1 BTC with a 10,000 USDT liability, while the 0.1 BTC collateral remains in the account balance (unlike isolated margin, where it's moved to the position).
Closing Positions
Closing logic differs based on whether the position assets and margin currency are the same.
Scenario 1: Position Assets Match Margin Currency
This applies to longs with base currency margin or shorts with quote currency margin. The closing process prioritizes using the position's available assets to repay the debt. The "reduce-only" option is available.
- Closing via Position Interface: Market and limit orders will use the position's assets to buy back the borrowed amount. Any remaining assets are returned to the account balance.
- Closing via Trading Interface (Not Reduce-Only): If an order exceeds what's needed to close the position, the excess can result in opening a new position in the opposite direction, using available balance from the main account as its margin.
Scenario 2: Position Assets Differ from Margin Currency
This applies to shorts with base currency margin or longs with quote currency margin. Closing only uses the position's assets. If these are insufficient to cover the debt, the account's margin balance is used to cover the difference.
- Closing via Position Interface: The entire position asset is sold. If the proceeds cover the debt, the remainder is returned. If not, the account's margin balance is used to cover the shortfall.
- Closing via Trading Interface (Not Reduce-Only): Selling more than the position's asset quantity will first close the existing position. The remainder of the order will open a new反向 position, using the main account's available balance as margin.
Cross Margin for Perpetuals and Futures
Perpetual and futures contracts support both one-way and two-way (hedged) position modes.
Key Position Fields for Perpetuals/Futures
- Position Quantity (pos): Positive for long positions, negative for short positions (in one-way mode).
- Average Opening Price (avgPx): Calculated as a volume-weighted average.
- Unrealized P&L (upl): Calculated differently for coin-margined (inverse) and USDT-margined (linear) contracts.
- Return on Equity (uplRatio): P&L / Initial Margin.
- Initial Margin (imr): The collateral required to open the position, based on notional value and leverage.
- Maintenance Margin (mmr): The minimum collateral required to keep the position open, based on notional value and the tiered maintenance rate.
Cross Margin for Options
Key Position Fields for Options
- Position Quantity (pos): Positive for long (buyer) positions, negative for short (seller) positions.
- Current Market Value (optVal): Position Quantity Mark Price Contract Multiplier (if applicable).
- Unrealized P&L (upl): (Mark Price - Average Entry Price) Position Quantity Contract Multiplier.
- Return on Equity (uplRatio): (Mark Price - Avg Entry Price) / Avg Entry Price for buyers; (Avg Entry Price - Mark Price) / Avg Entry Price for sellers.
- Initial Margin (imr): 0 for buyers (option premium paid). For sellers, it is calculated based on the option's risk parameters.
- Maintenance Margin (mmr): 0 for buyers. For sellers, it is a calculated value that must be maintained.
Risk Management and Liquidation
The system employs a two-layer risk check: Auto-Deleveraging (ADL) Cancellation and Pre-Liquidation. This helps maintain normal trading activity and prevents mass order cancellations or sudden liquidations due to insufficient margin.
Auto-Deleveraging (ADL) Cancellation
This mechanism cancels some open orders if account risk rises above a certain (but not yet critical) level to restore a safer state and avoid triggering a full pre-liquidation cancelation.
- Rules trigger based on available equity versus maintenance margin requirements for open orders.
- If available balance falls below zero, all isolated margin opening orders, sell orders for that currency, and option buy orders are canceled.
Pre-Liquidation Check
Forced liquidation is triggered when the Maintenance Margin Ratio reaches 100%. A warning is issued when this ratio falls below 300%.
If the ratio hits <=100%, the system cancels orders according to predefined rules per product type (e.g., futures, margin, options). If the account remains under-margined after order cancellation, forced liquidation begins.
Liquidation occurs in three stages to minimize market impact:
- Offsetting Hedged Positions: First, any perfectly offsetting long/short positions in the same contract (in two-way mode) are liquidated.
- Delta-Neutral Reduction: If risk remains, the system liquidates positions that are hedged in terms of delta (price sensitivity) to reduce risk while keeping the account's overall delta exposure stable.
- Non-Hedged Reduction: Finally, if needed, remaining positions are liquidated based on which liquidation most effectively improves the account's health, often starting with the largest or riskiest positions.
If liquidation results in negative equity, the platform's insurance fund may be used to cover the deficit, generating a clawback bill.
Frequently Asked Questions
What is the main advantage of using cross margin in Portfolio Margin Mode?
The primary advantage is capital efficiency. All positions sharing a settlement currency pool their collateral, allowing profits in one position to offset losses in another. This maximizes your available margin for new trades and can provide a buffer against liquidation.
How does isolated margin differ from cross margin in this mode?
Isolated margin quarantines the allocated collateral for a single position. Its risk is calculated separately, and its liquidation does not affect other positions in your account. This is ideal for hedging or trading highly volatile assets where you want to strictly define your maximum loss per trade.
What happens if my available margin becomes negative?
A negative available margin is a critical warning sign. The system will first cancel open orders to free up collateral. If the account's health does not improve and the maintenance margin ratio hits 100%, the forced liquidation process will begin on your positions to restore a positive equity balance.
Can I use both cross and isolated margin strategies simultaneously?
Yes, the mode is designed for flexibility. You might hold long-term, lower-risk positions in cross margin to benefit from shared collateral, while simultaneously opening speculative, high-risk trades using isolated margin to contain their potential losses.
What is the 'reduce-only' option when closing a position?
A reduce-only order ensures the trade will only ever decrease your existing position size. It cannot increase your exposure or open a new position in the opposite direction. This is a valuable risk management tool for exiting trades without accidentally adding new risk.
Where can I see my current maintenance margin ratio?
Your maintenance margin ratio for each currency is displayed in your account balance overview under the field mgnRatio. Monitoring this figure is essential for understanding your real-time risk level and avoiding liquidation.
This document is for informational purposes only. It is not intended to provide investment, tax, or legal advice, nor should it be considered an offer to buy, sell, hold, or any solicitation of any product or service. Digital asset trading carries a high level of risk and may not be suitable for all investors. You should carefully consider your investment objectives and risk appetite before deciding to trade. Past performance is not indicative of future results.