Trading Mechanism

Publicat la 8 apr. 2026Actualizat la 29 mai 20265 min citire

Order Book & Pricing

Price equals probability. Each share is priced between 0.001 and 0.999 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 minimum tick-size USDT; otherwise, the order's price will be rounded away.

  • 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.

  • IOC

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: no settlement fee

  • For the losing side: no settlement fee

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