An at-auction market order is available only during the pre-market opening period. Without a specified price, it is filled at the 「Calculated Opening Price」 of the Hong Kong Stock Exchange. All at-auction market orders will be matched in time priority order, and unmatched at-auction orders will be converted into limit orders at the 「Calculated Opening Price」 when the market opens.
Only certain Hong Kong futures are supported: Hang Seng Index Futures, Hang Seng China Enterprises Index Futures, Mini-Hang Seng Index Futures, Mini-Hang Seng China Enterprises Index Futures