Multicollateral Margin
Last updated: Aug 7, 2026
Use supported assets such as USDT and WETH to fund a single cross-margin perps account. This page is the conceptual overview. For step-by-step collateral operations, see Depositing Collateral and Withdrawing Collateral.
Overview
Synthetix supports unified margin. All supported collateral types in a subaccount contribute to that subaccount's account value, while perpetual markets remain quoted and settled in USDT.
You can:
- Deposit USDT or supported non-USDT collateral such as WETH.
- Trade USDT-settled markets using your combined collateral value.
- Withdraw each asset separately, subject to margin, balance, and debt limits.
- Swap non-USDT collateral into USDT when your account has USDT debt.
Trading fees, funding, and realized PnL settle into the USDT balance. If you hold mostly non-USDT collateral, your USDT balance can go negative during normal trading.
How it works
- Deposit supported collateral into a subaccount.
- The account receives margin credit based on each asset's value. USDT counts at face value; non-USDT collateral contributes its haircut-adjusted value.
- Open or manage positions in USDT-settled markets.
- Fees, funding, and realized PnL update the USDT balance.
- If the USDT balance becomes debt, repay voluntarily with Swap or reduce risk before forced auto-exchange becomes possible.
USDT debt
Your USDT balance can become negative during normal trading due to:
- Trading fees
- Funding payments
- Realized losses when positions are reduced or closed
A negative USDT balance is only treated as debt after positive unrealized PnL is considered. A winning open position can temporarily offset negative USDT.
| Situation | What happens |
|---|---|
| Open positions, negative USDT, positive UPNL covers it | Allowed - not treated as debt. Swap not available. |
| Open positions, negative USDT, UPNL does not fully cover | USDT debt exists - backed by collateral. LTV caps and Swap apply. |
| Close positions with USDT debt remaining | Debt is not auto-repaid. Use Swap voluntarily, or forced auto-exchange if debt exceeds allowed limit. |
| Debt exceeds allowed limit | Forced auto-exchange can convert non-USDT collateral to USDT. |
| Winning position, negative USDT | Positive UPNL can support USDT withdrawals and may eliminate effective debt. |
Viewing Borrowing Information
You can monitor your borrowing from the Borrowing tab in the Portfolio Table.
The Borrowing table provides a summary of your current USDT debt, borrowing capacity, accrued interest, and the actions available to manage your borrowed balance.
If your account has no borrowing activity or borrowing capacity, some values or actions may be unavailable until additional collateral is deposited or borrowing becomes available.
| Column | Description |
|---|---|
| Asset | The borrowed asset. Currently this is USDT. |
| Borrowed Amount | The total amount of USDT currently borrowed by your account. |
| Interest Rate (Hourly) | The hourly interest rate applied to your borrowed USDT balance. |
| Accrued Interest | Interest that has accumulated on your borrowed USDT balance and has not yet been repaid. |
| Available to Borrow | The additional amount of USDT your account can borrow before reaching its Max. Borrow limit. |
| Max. Borrow | The maximum USDT borrowing limit available to your account. This is determined by your collateral value, LLTV limits and borrowing tier. |
| Unrealized PnL | Positive unrealized PnL may offset negative USDT when determining whether effective debt exists. |
| Actions | Repay opens the Swap flow to repay USDT debt. Transfer and Deposit open their respective workflows. |
Swap (voluntary collateral exchange)
Use Swap on any non-USDT balance row to convert collateral into USDT.
Swap is available when you have USDT debt: negative USDT that is not fully covered by positive unrealized PnL. If USDT shows negative but a winning open position backs it, Swap may be unavailable because there is no effective debt to repay.
You can also select Repay from the Borrowing table to open the Swap flow and convert supported non-USDT collateral into USDT.
The Transfer and Deposit actions provide shortcuts to their respective workflows, allowing you to move assets between accounts or add additional collateral.
How it works:- Select the source asset and amount.
- Review the estimated USDT received after fees.
- Confirm. Collateral is sold and you receive USDT minus a fee.
Swapping to repay debt improves account health and can restore withdrawable margin when debt or LTV constraints are limiting withdrawals.
Auto-exchange
Auto-exchange converts non-USDT collateral to USDT without manual action. It protects the protocol and keeps accounts solvent.
When forced auto-exchange runs
Forced auto-exchange runs automatically during account health checks when your USDT debt exceeds your allowed debt limit.
Allowed debt is the lower of:
- Sum of (each non-USDT asset's Collateral Value x its LLTV)
- Your tier's Max. Borrow
When breached, the system sells non-USDT collateral until debt is back within limits.
Asset selection
The system sells assets with the lowest haircut first (deterministic tie-break by asset name when haircuts are equal). Forced exchanges use a higher fee rate than voluntary Swap.
LLTV and LTV
| Term | Meaning |
|---|---|
| LTV (Loan-to-Value) | Your current USDT debt divided by total adjusted non-USDT collateral value. Shown per asset row when you have debt. |
| LLTV (Liquidation LTV) | Maximum LTV before forced auto-exchange for that asset. Shown in the balances table. |
| Max. Borrow | The maximum USDT debt your account can support based on your collateral, LLTV limits, and borrowing tier. |
If your LTV reaches an asset's LLTV, collateral may be automatically exchanged until your debt returns within acceptable limits.
Example (WETH, LLTV 80%) - If your debt is 80% or more of your non-USDT collateral value, WETH may be sold to USDT automatically at best available prices minus the forced-exchange fee.
Account health checklist
When using non-USDT collateral, regularly monitor:
- Collateral Value - Haircut-adjusted collateral that contributes toward margin.
- Available Margin - Margin available to open or increase positions.
- Unrealized PnL - May offset negative USDT while positions remain open.
- LTV and LLTV - Your current debt relative to collateral limits.
- Borrowed Amount - Your current outstanding USDT debt.
- Available to Borrow - Remaining borrowing capacity before reaching your account limit.
- Max. Borrow - The maximum USDT your account can borrow.
See also
- Depositing Collateral - supported assets, deposit steps, minimums, and account caps.
- Withdrawing Collateral - withdrawal limits, USDT caps, LTV constraints, and fees.
- Leverage & Margin - Adjusted Account Value, haircuts, and collateral price risk.
- Fees - withdrawal, Swap, auto-exchange, gas, and trading fees.
- Liquidations - how collateral value affects liquidation risk.
- Subaccounts - collateral isolation between subaccounts.
- FAQ - common multicollateral troubleshooting questions.