OKX listing mechanism

Published on Apr 27, 2018Updated on Feb 23, 20266 min read7,443

Introduction

To support orderly market openings and fair price formation, OKX applies different listing mechanisms when opening trading for new spot pairs. The applicable mechanism will be announced in advance based on the characteristics of the asset.The listing mechanisms supported on OKX include:

  • Call Auction

  • Pre-open

Call Auction

What is a Call Auction?

A Call Auction is a listing mechanism where buy and sell orders are collected over a fixed period and matched at a single opening price when the auction ends.This mechanism is generally applied to newly listed assets that require price discovery at the start of trading.

Trading sequence

During a call auction, trading follows the sequence below:

  1. Start of Call Auction period

    1. Users may place limit buy and sell orders.

    2. Orders are collected but are not executed.

    3. Users may place, cancel, or modify orders during this period.

  2. Final auction period (last 5 minutes)

    1. Users may continue placing limit buy and sell orders.

    2. Order cancellation and modification are no longer supported during this period.

  3. Auction ends

    1. All eligible orders are matched at a single opening price.

    2. Continuous trading begins shortly after the auction ends.

Order rules

  • Supported order type: Limit orders only

  • Market orders: Not supported

  • Trading fees are charged only on executed orders

  • All eligible users may participate in the Call Auction

Orders that are not executed during the auction will remain in the order book after continuous trading begins.

Opening price determination

The opening price in a Call Auction is determined based on the following principles:

  • The price that allows the highest trading volume

  • At that price:

    • All buy orders priced higher than the opening price are fully executed, or

    • All sell orders priced lower than the opening price are fully executed

  • Either the buy side or the sell side at the opening price must be fully filled

The resulting price becomes the official opening price of the trading pair.

Indicative opening price

During the Call Auction period, OKX may display an indicative opening price for reference purposes.

  • The indicative opening price may change as orders are placed, cancelled, or modified.

  • The indicative opening price does not represent the final execution price.

If an opening price is displayed on the trading chart and provided by the project team, it is for reference only and does not affect order execution.

After the Call Auction

After the Call Auction ends:

  • Orders executed during the Call Auction are completed at the official opening price.

  • Continuous trading begins shortly after the auction ends.

  • Remaining unfilled limit orders stay active in the order book.

Additional trading rules apply during the first 5 minutes after the Call Auction:

  • Market orders are not supported during the first 5 minutes after trading begins.

  • This includes TP/SL orders that meet trigger conditions during this period will not be triggered and will be cancelled.

  • Orders placed during this period are subject to a maximum order size of 10,000 USD per order.

  • These limits would be lifted once the five minutes have concluded.


Pre-open

What is Pre-open?

Pre-open is a listing mechanism that allows users to place orders in advance before trading officially begins for a spot trading pair.During the pre-open period, orders are collected but no trades are executed. Order execution and fee charging follow normal trading rules only after official trading starts.

Trading sequence

During pre-open, trading follows the sequence below:

  1. Pre-open period

    1. Users may place limit buy and sell orders.

    2. Orders are collected but are not executed.

    3. Users may place, cancel, or modify orders during this period.

  2. Pre-open ends

    1. Orders that meet the applicable pricing requirements are retained.

    2. Orders priced outside the permitted range may be cancelled.

  3. After trading begins

    1. Orders are matched according to normal trading rules.

    2. Trading fees are charged only on executed orders.

Price limits and order cancellation

During pre-open, orders must comply with the applicable price limits based on the pre-open reference or indicative price.

  • Buy orders priced above the upper price limit will not be allowed.

  • Sell orders priced below the lower price limit will not be allowed.

  • At the end of the pre-open, buy orders priced above the reference price will not be cancelled.

  • At the end of the pre-open, sell orders priced below the reference price will not be cancelled.

The applicable price limits and reference prices are determined prior to the start of trading and may vary by listing. Relevant details will be announced in advance.

Order rules

  • Supported order type: Limit orders only

  • Market orders: Not supported

  • All eligible users may participate in pre-open

Orders that meet the pricing requirements will remain in the order book when trading begins.Orders that do not meet the pricing requirements may be cancelled at the end of the pre-open period.

After the Pre-open

After the pre-open ends:

  • Continuous trading begins shortly after the pre-open ends.

  • Previously placed limit orders stay active in the order book.

Additional trading rules apply during the first 5 minutes after the pre-open:

  • Orders placed during this period are subject to a maximum order size of 10,000 USD per order.

  • These limits would be lifted once the five minutes have concluded.

FAQ

  1. How long does the Call Auction or Pre-open period last?

The duration of the Call Auction or Pre-open period may vary by trading pair. Typically, both call auctions and pre-open periods last for an hour.

  1. What types of instruments support Call Auction or Pre-open?

Call Auction and Pre-open mechanisms are used for spot and perpetual futures trading pairs during listings. The applicable opening mechanism for each trading pair will be specified in the listing announcement.

  1. Is there a limit to the number or size of orders users can place during the Call Auction?

Yes, we apply a limit on the total size of orders that applicable users can place during the call auction. Please refer to the specific listing announcement for more details.

  1. Why is the indicative price different from the opening price shown on the trading chart?

In order to provide more trading information, following the end of the call auction, OKX will display the project team's opening price at the commencement of continuous trading as the initial price of the trading chart. The project team's opening price is provided by the token project team usually based on the valuation of the project. This project team's opening price is displayed for information purpose only, and is not determined by the call auction mechanism, and will not impact the prices where you will execute the orders.

  1. Can the best bid price be higher than the best ask price during the pre-open period?

Yes. During the pre-open period, orders are collected but not executed. As a result, the displayed best bid price may be higher than the best ask price. Orders are matched only after official trading begins and according to normal trading rules.