Most companies listed on Chinese exchanges will offer two shares classes: A-shares and B-shares. B-shares are quoted in foreign currencies (such as the U.S. dollar) and are open to both domestic and foreign investment (provided that locals set up a foreign currency account), while A-shares are only quoted in Chinese renminbi.
A-shares experienced explosive growth in the 2005-2007 period as restrictions preventing investment by Chinese citizens slowly began to peel away. In fact, demand was so high for A-shares that they would trade for much higher valuations than what the same stock could be purchased for on a different exchange.
The Peoples’ Republic of China is working to blend the two classes of stock together, and eventually allow direct foreign investment in mainland companies. It is one of many major financial reforms that the advanced economies of the world hope will occur in the next several years; there is a tremendous amount of pent-up demand for Chinese equity, provided that regulations become uniform and reporting requirements are in-line with global standards.