All margin is posted in 'USD' in your wallet. USD can be funded by depositing either USDC or TUSD.
By default all positions use the same collateral pool, and all USD, BTC, and USDT in your wallet count as collateral. Each subaccount has one central collateral wallet and uses portfolio margining for the account. Each subaccount has separate margin and collateral from other subaccounts.
If you want to use isolated margin create a subaccount for that position and move in collateral.
An account can only increase its position as long as its Margin Fraction is above its Initial Margin Fraction. For small positions, this means that the Margin Fraction must be at least 5%, meaning that accounts can only initialize positions to a maximum of 20x leverage. As your position size increases, so does your Initial Margin Fraction.
In addition, you can select a maximum leverage (per subaccount) on your account page. You may not put on a position that would put your leverage higher than that. (I other words--your maximum initial leverage is min(1/initial margin fraction, account leverage).
For instance, if you deposit $1,000 of collateral into your account, then the maximum position size you can put on is:
3x Leverage: $3,000
5x Leverage: $5,000
10x Leverage: $10,000
20x Leverage: $20,000
If your Initial Margin Fraction is 12%, then that means that your maximum leverage is 1/12% = 8.333x, so if you deposit $1,000 of collateral you could put on a position of size $8,333.
If you Margin Fraction falls below your Maintenance Margin Fraction, your account will begin to get liquidated. For instance, if your maintenance margin fraction is 6%, then you will begin to get liquidated once you are 16.66x leveraged.
If you drop below maintenance margin, the FTX risk engine will send liquidation orders in the market to close down your position.
See here for more details about the liquidation engine.
Balances of the following coins also count towards collateral:
See here for more details.
FTX Crypto Derivatives Exchange: https://ftx.com
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