The Hong Kong Stock Exchange (HKEX) is a unified stock exchange that is the result of the merger of 4 separate exchanges. It was incorporated in 1980, but a formal stock market has existed since 1891. HKEX works with an automatic Order Matching and Execution System (AMS) since 1993 and is headquartered in Hong Kong, an autonomous territory in China and one of the world's leading international financial centres. It has 2,062 listings and a market capitalization of 29.42 HKD trillion.
Among the listings are well-known and actively traded companies such as Tencent, PetroChina, Sinopec, HSBC and the Evergrande Group. The main stock index is the Hang Seng Index (HSI) which tracks the performance of the 50 largest companies of the Hong Kong stock market from four distinct sectors. As such, it is the benchmark indicator for all Hong Kong stocks, much like a Dow Jones Index for Hong Kong. Another key index is the S&P/HKEX GEM, representing 75% of HKEX by market capitalization.