Trading Sessions: Pre-opening, Continuous Trading and the Closing Auction

Orders from 9:00, trading from 9:30

The pre-opening session is a call auction: orders are entered 9:00–9:15, can't be cancelled 9:15–9:20, the opening price is set by random matching between 9:20 and 9:22, and then trading pauses until 9:30.

Morning session, lunch, afternoon session

The 9:30–12:00 morning session and 13:00–16:00 afternoon session are continuous trading: orders are matched as they arrive. 12:00–13:00 is the lunch break, with no matching.

Closing auction: random close

After 16:00 comes the closing auction: a reference price is set first, then orders are collected, and the market closes at a random moment between 16:08 and 16:10, matching most stocks' closing price at a single price.

Key takeaways

• 9:00–9:30 is the pre-opening session: no cancelling after 9:15, and the opening price is set by random matching between 9:20 and 9:22.
• The 9:30–12:00 morning session and 13:00–16:00 afternoon session are continuous trading, where orders match as they arrive; 12:00–13:00 is the lunch break.
• From 16:00 there's a closing auction session that closes at a random moment between 16:08 and 16:10, setting most stocks' closing price.
• Hong Kong is in the same time zone as Beijing and Taipei; if you watch from elsewhere, convert to your own time first.

Try it yourself

You can do these exercises in this lesson's interactive simulation:

1. Press ▶ and stop at 9:17: can you still cancel? What is the exchange doing?
2. Drag the time to 9:25: can you enter new orders now?
3. Drag to 12:30 and 16:09: which sessions are these?
4. Set “My time zone” to London and toggle summer and winter: what time does Hong Kong open in London?

Quiz and explanations

1. At 9:17 you want to cancel an order you placed in the pre-opening session. What happens?

Answer: You can't cancel; you can only wait for the matching result.9:15–9:20 is the no-cancellation period of the pre-opening session: orders can't be cancelled or amended.

2. How is the closing price of most Hong Kong stocks set?

Answer: The single price matched in the closing auction session.The closing auction session after 16:00 collects orders, closes at a random moment between 16:08 and 16:10, and matches them at a single price to set the close.

3. You place a buy order at 12:30 Hong Kong time. What happens?

Answer: The exchange isn't matching; it can fill only after the 13:00 afternoon session starts.12:00–13:00 is the lunch break and the exchange doesn't match; some brokers take the order and send it when the afternoon session starts.

Terms in this lesson

• call auction (Call Auction): Orders are collected for a while without trading, then all matched at once at a single price, often used at the open and close.
• closing auction (Closing Auction): For a few minutes before the close, orders are collected without trading, then matched all at once at a single price, which becomes the closing price.
• continuous trading (Continuous Trading): Normal trading after the open: each new order is matched against the order book as soon as it arrives, so the price changes with every trade.
• pre-opening session (Pre-opening Session): Hong Kong's daily 9:00–9:30 call auction: orders are collected without trading, the opening price is set by random matching between 9:20 and 9:22, and continuous trading starts at 9:30.