Explanation: The Bombay Stock Exchange Ltd. (BSE), earlier a regional stock exchange, converted into a national one in 2002. The biggest in India, it accounts for almost 75 per cent of total stocks traded in India and is the fifth largest in the world (based on market capitalization). There are at present four indices connected with the BSE:

1. Sensex: The sensitive index (i.e., Sensex) is a 30 stocks index of the BSE which was enlarged to include 50 stocks in 2000 but soon was cut down to the original level. This index represents the Indian stock market.
2. BSE-200: This is a 200-stock share index of the BSE (including the 30 stocks of the Sensex) which has its Dollar version too—the Dollex.
3. BSE-500: In mid-1999, the BSE came up with a 500-stock index representing major industries and many sub-sectors of the economy with information technology gaining a significant weightage.
4. National Index: An index of 100 stocks being quoted nationwide (Bombay, Delhi, Kolkata, etc.) was developed to give broader/wider representation of the stock market since the Sensex consists of only 30 stocks. The 30 stocks of the sensex are included in the National Index.

Source: Ramesh Singh