H-share companies are companies incorporated in Mainland China and whose listings in Hong Kong are approved by the China Securities Regulatory Commission (CSRC). Shares in these companies are listed in Hong Kong, subscribed for and traded in Hong Kong dollars or other currencies, and referred to as H shares. After finding its way into the Listing Rules, the term H share has been accepted and is widely used in the market. The letter H stands for Hong Kong.
Red chip companies are enterprises that are incorporated outside of the Mainland and are controlled by Mainland Government entities.
The most important difference between a red chip company and an H-share company is that a red chip company is not Mainland-incorporated.