The indices are created with sets of individual securities, which are called constituent values of the index. It is very useful to analyze the price variations of several companies at a glance.
A stock index is a numerical value, which is calculated according to the market prices of each of the securities that make up this index at a certain time. The profitability of an index is the variation of its value from one period to another.
Nowadays there are hundreds of indexes. The most important do not represent all the companies of an economy, not even all those that quote, but they are formed by the most significant (generally, by the largest). Therefore, when journalists talk about the stock market rising or falling, they mean a stock market index.
The main stock indices in the world are:
- SSE Composite Index (Shanghai, China)
- Hang Seng (Hong Kong)
- Nikkei 225 (Tokyo, Japan)
- Kospi (Seoul, South Korea)
- FTSE MIB (Milan, Italy)
- Ibex 35 (Madrid, Spain)
- CAC 40 (Paris, France)
- DAX 30 (Frankfurt, Germany)
- FTSE 100 (London, Great Britain)
- S & P / TSX 60 (Toronto, Canada)
- Dow Jones (New York, USA)
- S & P 500 (New York, USA)
- Nasdaq 100 (New York, USA)