On China stock markets, stocks are traded in lots.

I. Shanghai Stock Exchange and Shenzhen Stock Exchange 

In mainland China, stocks are traded in a lot size of 100 units. Trading in less than 100 shares can be sold during trading hours but can not be bought. However, placements of shares during rights issues are exempted and can be traded in odd units during the rights issue trading period.

II. Hong Kong Stock Exchange

On Hong Kong Stock Exchange, stocks are also traded in lots.  Unlike mainland China, the lot sizes are not unified into 100 shares per lot. Instead, every stock has an individual board lot size. There are three different types of lot size.

Board lot - A quantity of shares that is equal to or a multiple of a set figure that is set by each exchange.  For example, the board lot size of China Mobile is 500 shares per lot.  Accordingly, trading orders for China Mobile must be placed in lots of 500, such as 500, 1,000, 1,500, 2,000, etc. Trading in amounts which are not multiples of the board lot size are done in odd lot market. Each stock has an individual board lot size. An online broker will usually display this along with the stock price when you get a quote. You may also find lot size information from the stock exchanges or from this website.

Odd lot - A number of shares that are less than the board lot. For example, 499 shares of China Mobile is an odd lot that cannot be traded in board lot. The share price of odd lot is lower than that of the board lot.  There are odd lot traders who collect odd lots at lower prices to make board lots selling at regular board lot prices. How much the odd lot share is lower than board lot share depends on the popularity of the stock.  If a stock is unpopular, it is not a surprise to find its odd lot price lower than that of the board lot by more than 5%. Similarly, it is easier to trade odd lots of blue chips such as Hong Kong Bank than unpopular stocks, especially penny stocks.

Mixed lot - The amount of shares exceeds one board lot but is not enough to meet the next level, for example 602 shares of China Mobile trades in lots of 500 (one board lot of 500 + one odd lot of 102 = a mixed lot of 602).

All purchases must be made in board lots. Mixed and odd lot purchase lots will not be accepted.  Sales can be placed in mixed and odd lots. The sale of an odd lot will be made in the end of day auction.  For mixed lots the available board lot will be traded first with the remainder treated as an odd lot.

Related articles:

Trading of China Stocks – Ticks and Tolerance

List of Securities on H.K. Exchange Main Board with Lot Sizes & Stock Codes