Pre-opening Session

Updated at February 24th, 2025

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Contents

Introduction to the HKEX's Pre-opening Session Our Pre-opening Service

Introduction to the HKEX's Pre-opening Session

What is the Pre-opening Session? What are the features?

The Pre-opening Session is an additional trading session of 30 minutes (9:00 am - 9:30 am HKT), which takes place before the Morning Trading Session. It allows orders entered into the trading system, Automatic Order Matching and Execution System (AMS/3), to be matched and executed by auction at one single price.

The Pre-opening Session comprises of four different period as follows:

Order Input Period (15 minutes)
Hong Kong Time	9:00 am - 9:15 am
Highlights	Input of Limit Orders. Price Limit: ±15% of previous closing price (Not applicable to some cases¹) Orders are accumulated in HKEX trading system. Orders may be modified or cancelled.

No cancellation Period (5 minutes)
Hong Kong Time	9:15 am - 9:20 am
Highlights	Input of Limit Orders. Price Limit: Lowest ask & highest bid² (recorded at the end of Order Input Period) No modification or cancellation of Limit Orders.

Random Matching Period (2 minutes)
Hong Kong Time	9:20 am - 9:22 am
Highlights	Input of Limit Orders. No modification or cancellation of Limit Orders. Orders are matched randomly between 9:20am-9:22am Order will be matched at the final Indicative Equilibrium Price (IEP)³. And no order matching will be conducted if final Indicative Equilibrium Price (IEP) cannot be determined

Blocking Period (8 minutes)
Hong Kong Time	End of Random Matching Period - 9:30 am
Highlights	A break between the Pre-opening and the Continuous Trading Session. No input, modification or cancellation of orders.

Note:
1. In the absence of the Previous Closing (e.g. IPO stocks) and stocks resuming from trading suspension, 1st stage price limit checking will be relaxed for Order Input Period.
2. In case there is no buy order and/or sell orders recorded at the end of Order Input Period, the 2nd stage price limits will be same as the 1st stage price limits.
3. The final Indicative Equilibrium Price (IEP) will be used as the market-opening price for the corresponding security.

What are the applicable securities for Pre-opening Session (POS)?

All equities, including:
1. Depository receipts
2. Investment companies
3. Preference shares; and
4. Staple securities
Funds, including:
1. Exchange Traded Funds (ETFs) ; and
2. Real Estate Investment Trusts (REITS)
Leveraged and Inverse Products.
Exclude structured products, debt securities, equity warrants and rights.

How orders are matched in Pre-opening Session?

Orders will be matched in the Order Matching Period at the final Indicative Equilibrium Price (IEP), at which the maximum number of shares can be traded.

Would it be possible that no order is matched in Pre-opening Session?

Yes. There might be no order matched in the Pre-opening Session if no Indicative Equilibrium Price (IEP) is determined.

This can occur when there are only Limit Orders on one side, or Limit Orders on both sides but the highest bid price of the buy Limit Orders is lower than the lowest ask price of the sell Limit Orders.

Our Pre-opening Service

How do I trade in the Pre-opening Session?

Simply place your Limit Order at anytime between 4:11 pm and 9:22 am HKT. Our trading system will automatically convert your Limit Order into At-auction Limit Order (ALO) and submit it to the HKEX for the Pre-opening Session.

Can I place market order in the Pre-opening Session?

No. Market Order can only be placed and processed in the Continuous Trading Session (9:30 am - 12:00 pm and 1:00 pm - 4:00 pm HKT).

Can I change / cancel my orders in the Pre-opening Session?

You can change or cancel your order anytime. However, please note that the HKEX have restrictions on order cancellation or modification between 9:15 am to 9:30 am HKT. Therefore, your cancellation or modification requests made during this time will be processed at 9:30 am HKT.

What happens to my order if it is not filled in the Pre-opening Session?

Unfilled orders will continue to be processed as Limit Orders in the market until they are filled, cancelled or expired on the Good-till-date you have specified.

What if I do not want my orders automatically enter into the Pre-opening Session?

You can have single-day orders processed in the Continuous Trading Session for that day by placing the order any time from 9:22 am to 4:00 pm HKT.