The base period of S&P BSE SENSEX is 1978-79 and the base value is 100 index points. This is often indicated by the notation 1978-79=100. The calculation of S&P BSE SENSEX involves dividing the free-float market capitalization of 30 companies in the Index by a number called the Index Divisor. The credit for coining the term, Sensex, goes to Deepak Mohoni, a stock market analyst and IIT, Kanpur graduate and IIM, Calcutta alumnus. As of September 20, 2017, the index was hovering above the 30,000 mark. It is the oldest index in the country, while the Bombay Stock Exchange, now called BSE Limited, is the oldest exchange in Asia.