Positions and liability

STX does not simply debit the cost of an order when you place it and credit the payout when the market settles. It tracks several liability categories that change in real time as orders are placed, matched and settled.

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Wallet Fields

Field	Description
available_balance	Cash you can use to place new orders
buy_order_liability	Risk tied up in unfilled buy orders
sell_order_liability	Risk tied up in unfilled sell orders
position_premium_liability	Risk from contracts you currently hold

Your total exposure at any moment is the sum of all liability fields. The available_balance decreases when you place an order and can increase as orders are filled.

Subscribe to the balances channel to receive live updates whenever any of these numbers change.

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Order Liability

When you place an order the exchange immediately reserves the maximum possible loss; this is your order liability.

• Buy order: price × quantity. A limit buy of 10 contracts at $0.45 incurs $4.50 of order liability, reducing available_balance by the same.
• Sell order: (max_price − price) × quantity. A limit sell of 10 contracts at $0.36 on a market with max_price "1.0000" incurs (1.00 − 0.36) × 10 = $6.40 of order liability.

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Position Liability

When a trade executes on your order, order liability converts to position liability, the maximum loss on the contracts you now hold.

Importantly, this conversion often increases your available balance, because you filled at a better price than your limit. For example:

• You place a limit buy for 10 contracts at $0.45 → order liability $4.50, and available_balance drops by the same.
• Five fill at $0.43 → position liability for those 5 is $2.15, and order liability for the 5 still resting is $2.25. Total $4.40.
• available_balance therefore rises by $0.10: $0.02 saved on each of the 5 contracts that filled below your limit.

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Closing a Position

Placing an order on the opposite side of an existing position does not add new liability; it hedges the existing one.

Example: You hold a long position of 10 contracts bought at $0.45 ($4.50 of position liability). You place a sell order for 5 contracts at $0.60.

• The sell order does not change your available balance, because your total risk is unchanged.
• When the sell fills, a settlement is generated: 5 × (0.60 − 0.45) = $0.75 gross profit, added to available balance.
• Position liability drops to $2.25 (5 remaining contracts × $0.45).
• Your maximum possible loss is now 2.25 − 0.75 = $1.50 net, because you have locked in $0.75 of profit regardless of the final result.

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Settlement at Expiry

When a market resolves, open contracts settle at the market’s max_price or at $0. A push or settled result pays out between the two; see One market is one outcome.

• Won: position liability is released and you receive max_price × quantity. Net gain is (max_price − avg_price) × quantity.
• Lost: contracts settle at $0. The position liability is released, but you receive nothing back; your maximum loss on the position was already reserved.

All transactions are fully capitalized. There is no margin or leverage.

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Monitoring Positions in Real Time

Channel	What it delivers
balances	Available balance and liability totals
positions	Per-market position summary, including unrealized P&L
fills	Individual trade confirmations
settlements	Settlement records as they are created