|BSE 100 index is called as BSE National Index as it works as broad-based index reflecting the stock market at national level. Bombay Stock Exchange Limited, started compilation and publication of an index series called "BSE National Index" since 3rd January, 1989. The financial year 1983-84 has been chosen as the base year.
The equity shares of 100 companies from the "Specified" and the "Non-Specified" list of the five major stock exchanges, i.e. Mumbai, Calcutta, Delhi, Ahmedabad and Madras have been selected for the purpose of compiling the BSE National Index. The criteria for selection had been market activity, due representation to various industry-groups and representation of trading activity on major stock exchanges.