Trading Mechanism

Date de publication : 8 avr. 2026Date de mise à jour : 8 avr. 2026Lecture de 5 min

Order Book & Pricing

Price equals probability. Each share is priced between 0.01 and 0.99 USDT, directly reflecting the market's collective assessment of the probability that the event will occur.The order book is a list of all unfilled buy and sell orders in a market, divided into two sides (bid and ask).

Spread is the gap between the highest bid and the lowest ask. A tighter spread indicates better market liquidity.

Shared order book liquidity: Up and Down orders are automatically mapped to the opposite side using (1 − price), sharing liquidity:

  • Up Ask 0.66 → auto-mapped to Down Bid 0.34 (= 1 − 0.66) Down Ask 0.38 → auto-mapped to Up Bid 0.62 (= 1 − 0.38)

This means a sell order placed on the Up side simultaneously provides buy-side liquidity for the Down side, significantly deepening market liquidity.

Order Types

(1) Limit Order :Users specify a price to place an order, which enters the order book and waits for a counterparty. The order price must be a multiple of 0.01 USDT; otherwise, the order is rejected.

  • If the order can be matched immediately → filled immediately (Taker)

  • If it cannot be matched immediately → rests in the order book (Maker)

(2) Market Order: Users do not specify a price; the order is filled immediately at the best available price in the order book. Suitable for users who want to enter or exit positions quickly. The platform applies a worst-price protection mechanism to prevent excessive slippage on large orders.

  • Market buy orders are denominated in USD only.

  • Market sell orders are denominated in contracts only.

  • Market orders can match buyers and sellers of any size, but large orders may significantly impact prices. Always check order book depth before placing large trades.

For other order types, please refer to: Basic Order Types.

(3) Cancellation Rules: Users may cancel an order at any time before it is fully filled. For partially filled orders, only the unfilled remainder can be cancelled; the filled portion cannot be reversed.

Buy/Sell Mode vs. Open/Close Mode

Event Contracts support both Open/Close Mode and Buy/Sell Mode.

  • Open/Close Mode: Within the same event contract market, users can simultaneously hold both Up and Down positions. For example, holding 5 Up and 6 Down contracts at the same time. Full margin is required for all held contracts: margin for 5 Up contracts + margin for 6 Down contracts.

  • Buy/Sell Mode: Within the same event contract market, users can only hold a one-sided position (Up or Down). For example, if a user already holds 5 Up contracts and buys 6 Down contracts, the system freezes the required margin for 6 Down contracts and places the order simultaneously. Upon fill, since 5 Up contracts are already held, the system nets the positions: 6 Down − 5 Up = 1 Down net position. The margin for the original 5 Up contracts is released. Buy/Sell Mode improves capital efficiency.

Contract cost/Margin

Users are required to pay the full contract value upfront; however, the amount is not deducted from their accounts. This amount is frozen as margin with no liquidation mechanism.Each Up share + each Down share = 1.00 USDT (a complete pair). Under all circumstances, the total value of this pair is always equal to $1 USDT. Therefore, the system freezes only the purchase amount as margin, which covers the worst-case loss in full. No leverage, no margin calls.

  • Margin required for order = Number of shares × Purchase price + fees

  • Maximum loss = Margin used (total USDT paid at purchase)

  • Maximum gain = (1.00 − Purchase price) × Number of shares − fees

Event contract positions cannot be liquidated and do not participate in account-level liquidation processes. However, if the overall account risk is triggered in cross-margin mode, unfilled event contract orders may be cancelled to safeguard overall account health.

Example (buying Up): Buy 500 Up shares at 0.60 USDT; Margin ≈ 500 × 0.60 + fees > 300 USDT

Example (buying Down): Buy 500 Down shares at 0.40 USDT; Margin ≈ 500 × 0.40 + fees > 200 USDT

Positions & PnL

Position Value

Current position value = Number of shares held × Current market price

Note: This value (including floating PnL) cannot be used as margin.

Example: A user holds 200 BTC Up shares; current market price = 0.75 USDT:

Current position value = 200 × 0.75 = 150.00 USDT

PnL Calculations(1) Held to expiry and settled:

  • Winning side: each share redeemed at 1.00 USDT, minus settlement fee

  • Losing side: shares become worthless; no settlement fee

(2) Early close before expiry:

Realized PnL = (Average sell price − Average buy price) × Quantity sold − sell fee

(3) Floating PnL (floating during holding period):

Floating PnL = (Current mid-market price − Average buy price) × Shares held

Fees

Trading Fee Formula

  • Taker fee = K1 × C × (P × (1 − P))

  • Maker fee = K2 × C × (P × (1 − P))

Settlement Fee Formula

  • For the winning side: 0.01%

  • For the losing side: no settlement fee

(Please refer to the fee schedule link for specific values.)