Price Limit Rules

[Estimated reading time: 3 minutes]

Overview

To prevent orders from filling at extreme prices far from the market, the system limits order prices so they stay within a reasonable range around the mark price (the "price protection band"). Orders outside this range are rejected outright.

This rule applies when opening and closing positions. It's designed to prevent abnormal fill prices caused by input errors or momentary order book imbalances, which keeps your trading safe.

 

Limit order price restrictions

Your order price must satisfy the following formulas:

• Buy order price ≤ mark price × (1 + price limit percentage)

• Sell order price ≥ mark price × (1 – price limit percentage)

Note:

• The price limit percentage varies by futures contract and adjusts dynamically with market liquidity.

• Always go by the actual values shown on the trading page for the relevant futures contract or on [Futures rules] page.This article explains only how the rule works and doesn't list specific figures.

 

Market order execution mechanism

When a market order reaches the matching engine, the system applies a dynamic price protection mechanism:

1. The price range widens gradually. Within 1–3 seconds, the system progressively widens the percentage range of prices at which orders are allowed to fill.

2. The widening stops at the limit. The range keeps widening until it reaches the price limit percentage set for that futures contract.

3. Any unfilled quantity is canceled. If the order isn’t fully filled within that time, the system automatically cancels the remaining quantity.You'll need to resubmit your order to complete the trade.