Limit Order

This order type allows matching at the specified price queue.

Enhanced Limit Order

This order type allows matching in up to five price queues (the best price queue to the fifth queue at four spread way), where the price of the trade generated is at or better than the limit price.

Unfilled orders after matching will be converted to limit orders at the input limit price.

Special Limit Order

This order type is effectively a marketorder with a limit price. However, there is no restriction on the limit price to be entered with respect to the best price on the other side of the market. A Special Limit Order can match up to five price queues (the best price queue to the fifth queue at four spread way) as long as the traded price is not worse than the limit price.

Unfilled orders will be rejected and will not be queued in market order book.

At Auction Order

This is a market order which can only be inputted for single price auction during the pre-open session. There is no need to specify the limit price and it will enjoy a higher auction matching priority. Unfilled at-auction orders will be cancelled after auction matching.
The order input period for At-Auction orders is 9:00a.m. - 9:20 a.m.

Any At-Auction order input during order matching period (9:20a.m. - 9:28a.m.) and blocking period (9:28a.m. - 9:30a.m.) will be subject to rejection.

At-Auction orders input out of the pre-opening session will be rejected.

The information is provided by HKex.