Margin of USDTMargined Swaps
In a digital asset derivatives market, users can join contract trading by using a certain percentage of assets based on the contract price as the financial guarantee for the performance of the contract. Such assets are the margin required for contract trading. After a position is opened, the margin required for holding the position will change with the latest price.
Isolated margin mode：the account equity for each swaps is calculated separately, and the occupied margin, PnL and margin ratio of each swaps will not affect each other.
Cross margin mode: All swaps under the cross margin mode share the USDT in the cross margin account as the margin, which indicates that all positions under the cross margin mode share the same account equity, and their PnL, occupied margin and margin ratio are calculated jointly.
In USDTmargined swaps trading, users can trade a swaps by using cross and isolated margin modes at the same time with the margin in each account calculated separately. Users could switch for cross or isolated mode without current positions being affected. For example, users could hold BTC/USDT (cross) and BTC/USDT (isolated) at the same time.
Margin Calculation
Position margin = Face value * Position Quantity * Latest price / Leverage
Example 1: A user buys 100 conts BTC/USDT swaps to open a long position, the face value of each contract is 0.001 BTC, the latest price is 5000 USDT, and the leverage is 10x, therefore according to the formula, the position margin=0.001 * 100 * 5000 / 10 = 50 USDT
Example 2: A user buys 100 conts ETH/USDT swaps to open a long position, the face value of each contract is 0.01 ETH, the latest price is 500 USDT, and the leverage is 10x, therefore according to the formula, the position margin= 0.01 * 100 * 500 / 10 = 50 USDT
Margin Rules
In order to maintain the stability of the Derivatives market and reduce the risk of large positions, Huobi Futures adopts a Tiered Margin system, as the available margin will be adjusted according to account equity and leverage used. When the account equity corresponding to the leverage used by the user exceeds a certain range, the margin available to open positions will be increased/decreased; Tiered margin limits vary in various futures/swaps, and the available margin range of isolated margin mode account is the same as that of cross margin mode account, the specific rules are as follows:
Please Note: Depending on risk level, Huobi Futures has determined that some assets with leverage over 1x shall be subject to limitation on Tiered margin; While other assets will not be restricted by Tiered margin in the case of 10x or lower leverage, BTC would be an example.
Unit: USDT
[searching trading limit of more trading pairs]
【The above data and indicator contents may be adjusted in real time according to market conditions, and the adjustments will be made without further notice.】
Note: For maximum scale of Differentiate Margin System, Available coefficient = 1 / Corresponding leverage
Assume the account equity of Tom’s BTC/USDT swaps is 5,000 USDT, then the higher the leverage the user selects, the smaller the available margin:
 When 1x 50x leverage is selected, the available margin will not change.
 When 75x leverage is selected, the account equity 5,000 USDT belongs to the available coefficient range of the second tier. The first 3,000 USDT belongs to the first tier, therefore will not be affected; For the part that exceeding 3,000 but lower than 23,000, its available margin equals to “the amount of that part * available coefficient”, therefore Tom’s tiered available margin under the 75x leverage = 3000+(50003000) *50%=4000 USDT;
 When 100x leverage is selected, the account equity 5000 USDT belongs to the available coefficient range of the third tier. The first 2500 belongs to the first tier, therefore will not be affected; For the second part that exceeding 2500 but lower than 4000, it belongs to the second tier whose available coefficient is 50%; hence the corresponding available margin is 2500+(40002500)*50%=3250 USDT. For the third part that exceeding 4000 but lower than 40,000, it belongs to the third tier whose available coefficient is 20%; hence the corresponding available margin equals to “the amount of that part * available coefficient”. Then, Tom’s tiered available margin under the 100x leverage = 3250+(50004000)*20%=3450 USDT.
Assume Tom transfers 100 million USDT to his cross margin account and uses 20x leverage for crossmargined BTC/USDT swaps trading. Now his position margin is 350,000 USDT. If Tom still wants to open a position of crossmargined ETH/USDT swaps under the 20x leverage, how much available margin he has?
 First, the 350,000 USDT position margin of BTC/USDT swaps under the 20x leverage has entered the available coefficient range of 2nd tier, therefore, we need to reversely derive the position margin actually occupied by this position: 250,000+(350,000250,000)/33.33%=550,000 USDT；
 Due to the fact that BTC/USDT has occupied 550,000 USDT, there are 1,000,000 – 550,000 = 450,000 USDT can be used for other positions, and it will also be affected by tiered available margin;
 If Tom still wants to open a position of crossmargined ETH/USDT swaps under the 20x leverage, based on the tiered available margin range of ETH/USDT, for the part that exceeding 300,000 but lower than 600,000, the corresponding available margin equals to “the amount of that part * available coefficient”. Then, Tom’s tiered available margin =120,000+ [(450,000300,000) *10%] =150,000 USDT.
Locked Margin Optimization Scheme
To improve asset utilization and to reduce position margin for users, Huobi USDTmargined Swaps implements locked margin optimization scheme when users have swaps with both long and short positions for the same coin.
When users have swaps contracts with both long and short positions for the same coin, locked margin optimization scheme could reduce part of users’ position margin. The formula is as below:
New position margin = Long position margin+ Short position margin – Locked margin * Optimization ratio of the locked margin

Position margin = Contract face value * Position quantity * Latest transaction price / Leverage
 Locked margin = min (Long position margin, Short position margin)
 Optimization ratio of the locked margin is 100%.
Note: New position margin (account) under the cross margin mode = Σ New position margin of all swaps under the cross margin account.
Example:
Tom holds a long position of 1000 conts BTC/USDT swaps and a short position of 800 conts of BTC/USDT swaps both in 20x leverage. The face value of each contract is 0.001 BTC. Assume the latest price of BTC/USDT swaps is 8000, the new position margin of Tom is calculated as following:
 Calculate Tom’s long and short position margin. According to the formula, Position margin = Face value * Position quantity * Latest price / leverage, then the Long position margin is 0.001 * 1000 * 8000 / 20 = 400 USDT, and the short position margin is 0.001 * 800 * 8000 / 20 = 320 USDT.
 Calculate Tom’s locked margin. According to the formula, Locked margin = min (Long position margin, Short position margin), then the locked margin is min (400, 320) = 320 USDT.
 Calculate Tom’s new position margin. According to the formula, New position margin = Long position margin+ Short position margin – locked margin * optimization ratio of locked margin=400 + 320－320 * 100% = 400 USDT.
 From above calculation we can get that in this optimization mechanism, the new position margin of Tom is 400 USDT, which is much lower than its original 400 +320 = 720 USDT.
Calculation for Available Asset for Transfer
Available Asset for Transfer = max {0, Currentperiod initial equity + Currentperiod transfer_in quantity  Currentperiod transfer_out quantity + min (Realized PnL, 0) + min (Unrealized PnL, 0)  max [ 0, f(Occupied)  max (0, Realized PnL)]} + max {0, [Realized PnL  f (Occupied)]} * Available coefficient of realized PnL.
Note: The available coefficient of assets settled periodically is 0, and the available coefficient of assets settled in realtime is 1.
Example 1: Assume Tom’s initial equity in BTC/USDT swaps account was 500USDT, and bought 100 conts swaps of a long position with leverage 5X and open price of 10,000USDT. When the latest price rises to 12,000USD, the available asset for transfer are calculated as below (transaction fees will be negligible):
Unrealized PnL = (12,000 – 10,000) * 0.001 * 100 = 200 USDT;
f(Occupied) =Occupied margin= 100 * 0.001 * 12,000 / 5 = 240 USDT;
Available asset for transfer = max [0, 500+00+0+0240] + 0 = 260 USDT.
Example 2: Assume Tom’s initial equity in BTC/USDT swaps account was 50,000USDT, and bought 100,000 conts swaps of a long position with leverage 100X and open price of 10,000USD. When the latest price reached 12,000USD, he closed 50,000 conts. Then the price declines to 9,000USD, at this time, the available asset for transfer are calculated as below (transaction fees will be negligible):
Unrealized PnL = (9,000 – 10,000) * 0.001 * 50,000 = 50,000 USDT;
Realized PnL = (12,000 – 10,000) * 0.001 * 50,000 = 100,000 USDT;
Occupied margin = 50,000 * 0.001 * 9,000 / 100 = 4,500 USDT;
However, when using the leverage 100X, the available margin is limited by the tiered margin and the corresponding available coefficient turns to be 20.00%, then the actual f(Occupied) needs to be calculated as below:
f(Occupied) = 4,000 + ( 4,500 – 3,250 ) / 20.00% = 10,250 USDT;
Available asset for transfer = max [0, 50,000+00+050,000] + [ 100,000 – 10,250] = 89,750 USDT.
In conclusion, when the account equity exceeded a certain range and used larger leverage, the available margin will be restricted by the tiered margin. Then the occupied margin actually required becomes more, and the remaining available asset for transfer becomes relatively less.