A
stock index or stock market index is a measurement of the value of a
section of the stock market. It is computed from the prices of
selected stocks. It is a tool used by investors and financial
managers to describe the market, and to compare the return on
specific investments.
An index is a mathematical construct, so it may not
invested in directly. A national index represents the performance of
the stock market of a given nation. Such as American S&P 500, the
Indian NSE,BSE, the Japanese Nikkei 225, and the British FTSE 100
etc.
