What is At-auction Limit Order?

An at-auction limit order is an order with a specified price. An at-auction limit order with a specified price at or more competitive than the final IEP (in case of buying, the specified price is equal to or higher than the final IEP, or in case of selling, the specified price is equal to or lower than the final IEP) may be matched at the final IEP subject to availability of eligible matching order on the opposite side. An at-auction limit order will be matched in price and time priority at the final IEP. No at-auction limit order will be matched at a price worse than the final IEP. If an IEP cannot be determined during the Closing Auction Session, the Reference Price will serve as the price for matching. The matching of applicable at-auction orders and at-auction limit orders will occur at the Reference Price instead and the matching mechanism will be same as matching at the IEP.

Any outstanding at-auction limit orders at the end of the Pre-opening Session will be carried forward to the Continuous Trading Session and treated as enhanced limit orders provided that the specified price of that at-auction limit order does not deviate 9 times or more from the nominal price. Such orders will be put in the price queue of the input price.

Opening Auction Session

Order placement time: Between 16:10 on a trading day and 09:22 on the next trading day, auction limit orders submitted before 09:00 will be stored by the trading system and automatically sent to the exchange after 09:00.

Order amendment and cancellation time: Order amendment and cancellation are not allowed after 09:15; before that, you may change or cancel orders and adjust price or quantity.

Order execution time: 09:20 – not later than 09:22

Order execution price: Reference equilibrium price

Unexecuted orders: Any unexecuted auction limit orders will automatically convert to limit orders and automatically enter the continuous trading session.

Closing Auction Session

Order placement time: Orders can be placed between 09:30 and 16:10 on a trading day. If an auction limit order is submitted before 16:01, it will be temporarily stored in the trading system and automatically sent to the exchange after 16:01. Orders submitted between 16:01 and 16:10 will be sent to the exchange immediately.

Order amendment and cancellation time: Order amendment and cancellation are not allowed after 16:06.

Order execution time: 16:08 – 16:10 (random execution)

Order execution price: Reference equilibrium price. If no final reference equilibrium price is established during the closing auction session, the reference price will be used as the final reference equilibrium price to match buy and sell orders and will become the closing price of the closing auction security. This price will also be used to match buy and sell orders in priority order (by order type, price, then time).

Unexecuted orders: Unexecuted orders will be cancelled at 16:10.

The above content is for reference only. Please click on the link below, subject to the information of the Hong Kong Stock Exchange.

PRE-OPENING SESSION (POS)（https://www.hkex.com.hk/global/exchange/faq/securities-market/trading/pre-opening-session?sc_lang=en）

CLOSING AUCTION SESSION (CAS)（https://www.hkex.com.hk/global/exchange/faq/securities-market/trading/cas?sc_lang=en#collapse-9）