Different stock exchanges focus on different types of stocks. Some indices are specifically global (such as the S&P Global 100) whilst others are national, listing only companies which are native to the country in question. Other indices focus only on specific business sectors – the NASDAQ index, for example, only lists tech stocks.
However, there are some multinational corporations which are tradable on more than one index; usually both a national index and an international one. Alibaba.com, for example, can be traded both on Hong Kong’s Hang Seng index and – after a highly publicised IPO last year – the New York Stock Exchange as well. Similarly, Credit Suisse can be traded both on the Zurich-based Swiss Market Index and the New York Stock Exchange. Some financial indices are tradable either in ‘Rolling Daily’ or ‘Futures’ formats, meaning that they can be traded either at their current price or at a price agreed on now for an option which will close automatically on a specific date.