It is a free-float market-weighted stock market index of 30 largest and most liquid companies listed on the Bombay Stock Exchange. These companies are representative of various industrial sectors of the Indian economy.
Established: It was established on 1 January 1986.
Base Year: The base value of the SENSEX was taken as 100 on 1 April 1979 and its base year as 1978–79.
Calculations: It is calculated based on a free float capitalisation method as it uses a company’s shares that are readily available for trading. The level of index at any point of time reflects the free float market value of 30 constituent stocks relative to a base period. It excludes restricted stocks that can't be sold easily, such as those held by corporate executives.
The index value has increased by over twenty five times since its inception.