Single-Price Auctions and the Regular Session

Orders from 8:30, trading from 9:00

8:30–9:00 is the opening single-price auction (dongsi-hoga): orders are collected without trading, and at 9:00 they're matched all at once at a single price to set the opening price.

No lunch break, and the close is an auction too

9:00–15:20 is continuous trading, with no lunch break. 15:20–15:30 is the closing auction, and the closing price is set in those 10 minutes.

Two more trading periods after the close

From 15:40 to 16:00 you can only trade at the closing price; from 16:00 to 18:00 orders are matched every 10 minutes, at prices within 10% of the close. Since 2025 the alternative trading venue Nextrade also offers trading that starts earlier and ends later (check the latest rules).

Key takeaways

• 8:30–9:00 is the opening single-price auction: orders are collected without trading, then matched all at once at 9:00 at a single price to set the opening price.
• 9:00–15:20 is continuous trading, where orders match as they arrive; there's no lunch break.
• 15:20–15:30 is the closing single-price auction, which sets the closing price.
• After the close there's after-hours trading: from 15:40 to 16:00 only at the closing price, and from 16:00 to 18:00 matched every 10 minutes at prices within 10% of the close.

Try it yourself

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

1. In the session simulator press ▶ and stop at 8:45: would an order placed now fill immediately?
2. Drag the time to 12:30: is the Korean market on a lunch break now?
3. Drag to 16:20: which session is this? What limits the trade price?
4. In the auction simulator switch to “good news” and play: how many ticks above the reference price is the open?

Quiz and explanations

1. You place a buy order at 8:45. What happens?

Answer: It queues and is matched with everything else in the 9:00 single-price auction.8:30–9:00 is the opening single-price auction: orders are collected without trading and matched all at once at 9:00 at a single price.

2. How is the Korean closing price set?

Answer: The price matched in the 15:20–15:30 closing single-price auction.15:20–15:30 is the closing single-price auction: for those 10 minutes orders are only collected, and at 15:30 they're matched at one price to set the close.

3. You place a buy order at 16:30. What happens?

Answer: It enters after-hours single-price trading, matched every 10 minutes at prices within 10% of the close.16:00–18:00 is after-hours single-price trading: orders are matched in a batch every 10 minutes, at prices within 10% of the day's close.

Terms in this lesson

• alternative trading venue (Alternative Trading Venue): A regulator-approved stock trading venue outside the exchange, such as Korea's Nextrade, operating since 2025 with longer hours and possibly different fees.
• 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.
• opening price (Opening Price): The first trade price of each trading day, set by an opening auction at many exchanges.
• price-time priority (Price-Time Priority): The matching rule: better-priced orders fill first, and orders at the same price queue in the order they arrived.
• single-price auction (dongsi-hoga) (Single-Price Auction): Korea's call auction: for a period orders are collected without trading, then matched all at once at a single price. There's one before the open and one before the close, and it's also used after a VI is triggered.