Shares traded on the Hong Kong stock market are traded in lots. For example, 500 shares per lot.
When placing an order for shares on the Hong Kong stock market you will need to ensure your order quantity is a multiple of the lot size. Upon selection of the Review Order button on the order pad a message will be displayed if your order does not meet the required lot size. This message will inform you of the lot size applicable for that security.
For value orders, the order quantity will round down to the nearest lot size.